arterial supply of head & neck

Arterial supply of head & neckArterial supply of head & neck

THE EXTERNAL CAROTID ARTERYTHE EXTERNAL CAROTID ARTERY

Course :Course : It begins at the bifurcation of the It begins at the bifurcation of the

common carotid artery opposite the common carotid artery opposite the appear border of the thyroid cartilage, appear border of the thyroid cartilage, and ascending upwards it at first lies and ascending upwards it at first lies deep to and then within the substances deep to and then within the substances of the parotid gland and ends by dividing of the parotid gland and ends by dividing into maxillary (internal maxillary) and into maxillary (internal maxillary) and superficial temporal arteries opposite the superficial temporal arteries opposite the level of the neck of the mandiblelevel of the neck of the mandible

Branches of the external carotid Branches of the external carotid artery :artery :

1.1. Superior thyroid Superior thyroid 2.2. Ascending pharyngeal Ascending pharyngeal 3.3. LingualLingual4.4. Facial Facial 5.5. Occipital Occipital 6.6. Posterior auricular Posterior auricular 7.7. Superficial temporalSuperficial temporal8.8. Maxillary. Maxillary.

Relation :Relation : Opposite the angle of the mandible it is Opposite the angle of the mandible it is covered superficially by the posterior belly of the covered superficially by the posterior belly of the digastric and the stylohyoid muscles. Between its origin digastric and the stylohyoid muscles. Between its origin and the posterior belly of digastric it is comparatively and the posterior belly of digastric it is comparatively superficial being overlapped only by the anterior margin superficial being overlapped only by the anterior margin of the sternocleidomastoid. It is crossed superficially by of the sternocleidomastoid. It is crossed superficially by the (common) facial vein and the hypoglossal nerve in the (common) facial vein and the hypoglossal nerve in this situation. Above the angle of the mandible it at first this situation. Above the angle of the mandible it at first lies posterior to the parotid gland and then embedded lies posterior to the parotid gland and then embedded into its substance. Medially it is related to the middle and into its substance. Medially it is related to the middle and inferior constrictor muscles of the pharynx and the inferior constrictor muscles of the pharynx and the external and the internal laryngeal nerves. external and the internal laryngeal nerves. Posterolaterally it is related to the internal carotid artery. Posterolaterally it is related to the internal carotid artery.

Arterial supply of head & neckArterial supply of head & neck INTRODUCTION INTRODUCTION ANGIOGENESISANGIOGENESIS STRUCTURE OF ARTERIES STRUCTURE OF ARTERIES GROWTH OF BLOOD VESSELS GROWTH OF BLOOD VESSELS A NOTE ON ANASTOMOSIS AND A NOTE ON ANASTOMOSIS AND

COLATERAL CIRCULATION. COLATERAL CIRCULATION. FUNCTION OF ARTERIAL WALL FUNCTION OF ARTERIAL WALL

Maintenance of blood flow and BP in Maintenance of blood flow and BP in diastolediastole

Propulsion of blood through coronary Propulsion of blood through coronary arteries. arteries.

Constriction and dilation of vessels. Constriction and dilation of vessels. EXAMINATION OF BLOOD VESSELS EXAMINATION OF BLOOD VESSELS

Clinical examination arteries Clinical examination arteries X-ray examination of blood vessels X-ray examination of blood vessels

(Angiography)(Angiography) ARTERIES OF BODY ARTERIES OF BODY Arteries of pulmonary circulation Arteries of pulmonary circulation

Arteries of systemic circulation.Arteries of systemic circulation. AORTA AORTA

Arch of aorta and its branches Arch of aorta and its branches Varation in branching pattern Varation in branching pattern

Common carotid artery Common carotid artery Surface anatomySurface anatomy

Course and relations Course and relations Developments Developments Carotid body Carotid body Applied surgical anatomy.Applied surgical anatomy. External carotid arteryExternal carotid artery

SUPERIOR THYROID ARTERY SUPERIOR THYROID ARTERY LINGUAL ARTERY LINGUAL ARTERY FACIAL ARTERY FACIAL ARTERY OCCIPITAL ARTERY OCCIPITAL ARTERY ASCENDING PHARYNGEAL ARTERY ASCENDING PHARYNGEAL ARTERY POSTERIOR AURICULAR ARTERY POSTERIOR AURICULAR ARTERY SUPERFICIAL TEMPORAL SUPERFICIAL TEMPORAL MAXILLARY ARTERY MAXILLARY ARTERY INTERNAL CAROTID ARTERYINTERNAL CAROTID ARTERY

APPLIED SURGICAL ASPECT APPLIED SURGICAL ASPECT CAROTID ARTERY LIGATION CAROTID ARTERY LIGATION

Indication selective carotid resection Indication selective carotid resection Evaluation Evaluation Carotid ligation –Carotid ligation –

operative and perioperative operative and perioperative management management

Alternatives to carotid ligation Alternatives to carotid ligation Prevention of carotid rupture Prevention of carotid rupture Management of spontaneous carotid Management of spontaneous carotid

rupture rupture Neck incision or carotid rupture Neck incision or carotid rupture Prevention of carotid blow out Prevention of carotid blow out

SUBCLAVIAN ARTERY SUBCLAVIAN ARTERY VERTEBRAL ARTERY VERTEBRAL ARTERY

RADITION EFFECTS ON ARTERIES RADITION EFFECTS ON ARTERIES AGE CHANGES IN ARTERIES AGE CHANGES IN ARTERIES REFERENCESREFERENCES

IntroductionIntroduction A successful out come of major head and neck surgery depends greatly on prevention of A successful out come of major head and neck surgery depends greatly on prevention of

two major causes. two major causes. Intra-operative and post operative, morbidity and mortality “Hemorrhage” Intra-operative and post operative, morbidity and mortality “Hemorrhage” Airway obstruction. Airway obstruction. Frequently these two entities are interrelated. As every one knows “Prevention is better Frequently these two entities are interrelated. As every one knows “Prevention is better

than cure”. than cure”. Prevention of hemorrhage depends on the Prevention of hemorrhage depends on the Meticulous surgical technique Meticulous surgical technique Through knowledge of head and neck anatomy Through knowledge of head and neck anatomy Proper preoperative evaluation of the coagulation factors essential for proper homeostasis. Proper preoperative evaluation of the coagulation factors essential for proper homeostasis. If hemorrhagic complication are anticipated and prevented, most major bleeding If hemorrhagic complication are anticipated and prevented, most major bleeding

complication can be avoided. complication can be avoided. The heart provides the major force that cause blood to circulate but the blood vessels carry The heart provides the major force that cause blood to circulate but the blood vessels carry

blood to all tissue of the body and back to the heart. In addition, the blood vessels blood to all tissue of the body and back to the heart. In addition, the blood vessels participate in the regulation of blood pressure and help to direct blood flow to tissue that participate in the regulation of blood pressure and help to direct blood flow to tissue that are most active. The intricacy and coordinated function of blood vessels make the design are most active. The intricacy and coordinated function of blood vessels make the design of complex urban water system seem rather simple in comparison. of complex urban water system seem rather simple in comparison.

The peripheral circulatory system can be divided into two sets of blood vessels. The The peripheral circulatory system can be divided into two sets of blood vessels. The systemic vessels transport blood through essentially, all parts of the body from the left systemic vessels transport blood through essentially, all parts of the body from the left ventricle and back to right atrium. The pulmonary verses. Transport blood from right ventricle and back to right atrium. The pulmonary verses. Transport blood from right ventricle through lung and back to the left atrium. The cardiovascular system ensures the ventricle through lung and back to the left atrium. The cardiovascular system ensures the survival of each tissue type in the body by supplying nutrients and removing waste survival of each tissue type in the body by supplying nutrients and removing waste products from tissues. products from tissues.

ANGIONESIS :ANGIONESIS : When pharyngeal arches form during 4th and 5th week of development, When pharyngeal arches form during 4th and 5th week of development,

each arch receives its own cranial nerve and its own artery. These arteries, each arch receives its own cranial nerve and its own artery. These arteries, the artic arches and from the aortic sac, the most distal part of the truncus the artic arches and from the aortic sac, the most distal part of the truncus arteriosus. The aortic arches are embedded in mesenchyme of pharyngeal arteriosus. The aortic arches are embedded in mesenchyme of pharyngeal arch and terminate in the right and left dorsal aortic. (In the region of the arch and terminate in the right and left dorsal aortic. (In the region of the arches the dorsal aortae, remain paired, but caudal to this region they fuse arches the dorsal aortae, remain paired, but caudal to this region they fuse to form a single vessel). to form a single vessel).

The aortic sac contributes a branch to each new arch as it form giving rise The aortic sac contributes a branch to each new arch as it form giving rise to a total of 5 pairs of arteries. (The 5th arch either never forms or forms to a total of 5 pairs of arteries. (The 5th arch either never forms or forms incompletely and then regresses. incompletely and then regresses.

Division of the truncus arteriosus by aortic pulmonary septum divides the Division of the truncus arteriosus by aortic pulmonary septum divides the outflow channel of the heart into ventral aorta and the pulmonary artery. The outflow channel of the heart into ventral aorta and the pulmonary artery. The aortic sac then forms right and left horns, which subsequently give rise to aortic sac then forms right and left horns, which subsequently give rise to branchiocephalic artery and the proximal. Segment of aortic arch branchiocephalic artery and the proximal. Segment of aortic arch respectively. respectively.

By day 27, most of the 1st aortic arch, has disappeared although a small By day 27, most of the 1st aortic arch, has disappeared although a small portion persist to form maxillary artery. portion persist to form maxillary artery.

Similarly, the second aortic arch disappear. The remaining portion of this Similarly, the second aortic arch disappear. The remaining portion of this arch are, hyoid and stapedial arteries . arch are, hyoid and stapedial arteries .

The 3rd arch is large; the 4th and 6th arches are in the process of formation. The 3rd arch is large; the 4th and 6th arches are in the process of formation. Even though the 6th arch is not completed, the primitive pulmonary artery is Even though the 6th arch is not completed, the primitive pulmonary artery is already prevent as a major branch. already prevent as a major branch.

The third aortic arch forms the common carotid artery and the 1st The third aortic arch forms the common carotid artery and the 1st part of the internal carotid artery. The remainder, of the internal part of the internal carotid artery. The remainder, of the internal carotid artery is formed by cranial portion of the dorsal aorta. carotid artery is formed by cranial portion of the dorsal aorta.

The external carotid artery is a sprout of the 3rd aortic arch. The external carotid artery is a sprout of the 3rd aortic arch. The 4th arch persists on both sides but it’s ultimate fate in different The 4th arch persists on both sides but it’s ultimate fate in different

on the right and left side. on the right and left side. On left – If forms part of arch of aorta between the left. Common On left – If forms part of arch of aorta between the left. Common

carotid and the left subclavian arteries. carotid and the left subclavian arteries. On right – It forms the most proximal segment of the right On right – It forms the most proximal segment of the right

subclavian artery. subclavian artery. 5th arch either never forms or forms incompletely and then 5th arch either never forms or forms incompletely and then

regresses. regresses. The vascular system, is both a conduit for the flowing blood and a The vascular system, is both a conduit for the flowing blood and a

dynamic system that control the distribution of blood in the body. dynamic system that control the distribution of blood in the body. The elastic arteries dampen the pulsatile outflow of the blood from The elastic arteries dampen the pulsatile outflow of the blood from

the heart to provide a more continuous flow of blood to the tissue. the heart to provide a more continuous flow of blood to the tissue. The arterioles, because of their smaller internal diameter, are the The arterioles, because of their smaller internal diameter, are the major site of resistance of blood flow changes in the diameter of major site of resistance of blood flow changes in the diameter of arterioles determine the amount of blood flowing. Through a arterioles determine the amount of blood flowing. Through a particular tissue bed .particular tissue bed .

STRUCTURE OF THE ARTERIESSTRUCTURE OF THE ARTERIES:: In the arteries the primary coat of endothelium, together with a supporting sub In the arteries the primary coat of endothelium, together with a supporting sub

endothelial layer of elastic tissue, is known as the inner tunic or tunica intima. The endothelial layer of elastic tissue, is known as the inner tunic or tunica intima. The secondary coat is subdivided into the middle (tunica media) and outer (tunica externa secondary coat is subdivided into the middle (tunica media) and outer (tunica externa or adventitia) tunics. The tunica externa consists chiefly of fibrous tissue, but the or adventitia) tunics. The tunica externa consists chiefly of fibrous tissue, but the media is composed of both muscle and elastic tissue, combined in varying media is composed of both muscle and elastic tissue, combined in varying proportions in different parts of the arterial tree. In the larger arteries the tunica media proportions in different parts of the arterial tree. In the larger arteries the tunica media is mainly elastic, in the medium-sized arteries elastic and muscular elements are is mainly elastic, in the medium-sized arteries elastic and muscular elements are evenly mixed, while in the smaller arteries the media is predominantly muscular. evenly mixed, while in the smaller arteries the media is predominantly muscular.

Tunica intima :Tunica intima :This consists of endothelium, surrounded by the internal elastic lamina, a thick sheet This consists of endothelium, surrounded by the internal elastic lamina, a thick sheet of elastic tissue which in histological section has a characteristic wavy appearance. of elastic tissue which in histological section has a characteristic wavy appearance. This appearance is in all probability due to the post-mortem contraction of the vessel, This appearance is in all probability due to the post-mortem contraction of the vessel, for it disappears to a considerable extent when the arteries are fully dilated. for it disappears to a considerable extent when the arteries are fully dilated.

Tunica media :Tunica media :The elastic tissue in the media is in the form of numerous separate sheets, The elastic tissue in the media is in the form of numerous separate sheets, concentrically arranged and overlapping one another. In transverse the internal concentrically arranged and overlapping one another. In transverse the internal sections these sheets are cut end no, and appear as wavy lines, thinner than elastic sections these sheets are cut end no, and appear as wavy lines, thinner than elastic lamina. lamina. Smooth muscle fibers are found in the tunica media. They have usually been thought Smooth muscle fibers are found in the tunica media. They have usually been thought to surround the vessel at right-angles to its long axis, and have therefore been called to surround the vessel at right-angles to its long axis, and have therefore been called circular; but not infrequently they are arranged in the form of spirals. In the larger circular; but not infrequently they are arranged in the form of spirals. In the larger arteries there is but little muscle present; as the arteries divide, muscle fibers appear arteries there is but little muscle present; as the arteries divide, muscle fibers appear in increasing numbers, while elastic tissue diminishes. In the smaller arteries and in increasing numbers, while elastic tissue diminishes. In the smaller arteries and arterioles the media is almost exclusively muscular.arterioles the media is almost exclusively muscular.

Tunica externa or adventitia :Tunica externa or adventitia :The outermost tunic consists mainly of connective tissues whose The outermost tunic consists mainly of connective tissues whose collagen fibers, particularly in the large arteries, impart great tensile collagen fibers, particularly in the large arteries, impart great tensile strength and so prevent excessive vasodilatation. strength and so prevent excessive vasodilatation. The artery with its three coats lies embedded in the surrounding The artery with its three coats lies embedded in the surrounding connective tissue, which varies in different parts of the body both in connective tissue, which varies in different parts of the body both in density and in extent to which the adventitia is attached to it. In density and in extent to which the adventitia is attached to it. In some regions the adventitia is surrounded by dense connective some regions the adventitia is surrounded by dense connective tissue to which it is very closely attached. The artery is thereby tissue to which it is very closely attached. The artery is thereby firmly anchored in position, and when cut cannot retract, since the firmly anchored in position, and when cut cannot retract, since the cut end is kept fixed and gaping wide open. Bleeding from such cut end is kept fixed and gaping wide open. Bleeding from such arteries is therefore particularly free; the arteries of the scalp and arteries is therefore particularly free; the arteries of the scalp and the palm of the and are of this type. the palm of the and are of this type. In the larger arteries the adventitia may form a loosely attached In the larger arteries the adventitia may form a loosely attached sheath which was been aptly compared to the outer tube of sheath which was been aptly compared to the outer tube of pneumatic tyre. In this sheath the blood vessels and nerves of the pneumatic tyre. In this sheath the blood vessels and nerves of the artery first ramify before they enter the media; the diffuse network of artery first ramify before they enter the media; the diffuse network of nerve fibers in the adventitia is the periarterial plexus. Stripping the nerve fibers in the adventitia is the periarterial plexus. Stripping the adventitia cuts off the nerve supply of the subjacent portion of the adventitia cuts off the nerve supply of the subjacent portion of the artery, and constitutes the operation of periarterial sympathectomy. artery, and constitutes the operation of periarterial sympathectomy. The network of blood vessels in the adventitia, and the fine The network of blood vessels in the adventitia, and the fine branches which they give to, and receive from, the tunica media, branches which they give to, and receive from, the tunica media, constitute the vasa vasorum. constitute the vasa vasorum.

FUNCTION OF THE ARTERIAL WALLFUNCTION OF THE ARTERIAL WALL : : Maintenance of blood flow and blood pressure in diastole:Maintenance of blood flow and blood pressure in diastole:

When the ventricle contract, the force of their contraction is expended partly When the ventricle contract, the force of their contraction is expended partly in driving blood through the arteries, and partly in stretching the elastic in driving blood through the arteries, and partly in stretching the elastic tissue in their walls. A pressure wave, expending the elastic vessel walls, tissue in their walls. A pressure wave, expending the elastic vessel walls, passes peripherally at high speed, and the distension of the wall is passes peripherally at high speed, and the distension of the wall is perceptible as the pulse wave. During diastole the stretched elastic tissue perceptible as the pulse wave. During diastole the stretched elastic tissue recoils on the contained blood, and produces a pressure which first closes recoils on the contained blood, and produces a pressure which first closes the aortic and pulmonary valves, thus preventing the backflow of blood into the aortic and pulmonary valves, thus preventing the backflow of blood into the relaxed ventricles, and then drives the blood forward through the the relaxed ventricles, and then drives the blood forward through the arteries. By providing a driving force for the blood during diastole, the elastic arteries. By providing a driving force for the blood during diastole, the elastic tissue of the arteries converts into a continuous flow one which would tissue of the arteries converts into a continuous flow one which would otherwise be intermittent. otherwise be intermittent.

Propulsion of blood through the coronary arteries:Propulsion of blood through the coronary arteries:The elastic recoil of the aorta also serves to drive blood through the The elastic recoil of the aorta also serves to drive blood through the coronary arteries to supply the heart. The coronary arteries arise from the coronary arteries to supply the heart. The coronary arteries arise from the aorta close to its origin from the left ventricle and their terminal branches aorta close to its origin from the left ventricle and their terminal branches ramify among the cardiac muscle fibers; ventricular contraction compresses ramify among the cardiac muscle fibers; ventricular contraction compresses these branches and impedes the flow of blood through them. It is only when these branches and impedes the flow of blood through them. It is only when the musculature of the ventricle is relaxed that blood can flow freely through the musculature of the ventricle is relaxed that blood can flow freely through the coronary vessels, and the drives force, for this flow is the elastic recoil of the coronary vessels, and the drives force, for this flow is the elastic recoil of aorta and larger arteries. If the elasticity of the aorta and its main branches aorta and larger arteries. If the elasticity of the aorta and its main branches is diminished, the immediate result will be lowering of the diastolic pressure, is diminished, the immediate result will be lowering of the diastolic pressure, and a diminution in the amount of blood flowing through the coronary and a diminution in the amount of blood flowing through the coronary arteries. arteries.

Constriction and dilatation of arteries:Constriction and dilatation of arteries:Contraction of the circular muscle fibers narrows the vessel, and if blood pressure and rate of Contraction of the circular muscle fibers narrows the vessel, and if blood pressure and rate of flow are unchanged, this diminishes the volume of blood flowing through it in a given time. flow are unchanged, this diminishes the volume of blood flowing through it in a given time. Narrowing of a vessel is termed vasoconstriction, and widening is vasodilatation. By means of Narrowing of a vessel is termed vasoconstriction, and widening is vasodilatation. By means of vasoconstriction and vasodilatation the flow of blood to part can be accurately regulated, in vasoconstriction and vasodilatation the flow of blood to part can be accurately regulated, in accordance with its functional needs. accordance with its functional needs. The caliber of an artery at any given moment represents a balance between two opposing forces, The caliber of an artery at any given moment represents a balance between two opposing forces, one being the fluid pressure of the blood in the lumen, exerted outwards in all directions and one being the fluid pressure of the blood in the lumen, exerted outwards in all directions and dilating the vessel, the other the contraction of the circular muscle, constricting the vessel. In dilating the vessel, the other the contraction of the circular muscle, constricting the vessel. In large arteries with but little muscle the tension of the elastic tissue has the same effect as muscle large arteries with but little muscle the tension of the elastic tissue has the same effect as muscle contraction, except that it obeys purely mechanical laws and is not under nervous control. All contraction, except that it obeys purely mechanical laws and is not under nervous control. All arteries with muscle fibers in their wall receive a vasomotor nerve supply, through which the tone arteries with muscle fibers in their wall receive a vasomotor nerve supply, through which the tone or the degree of contraction of these fibers can be regulated. or the degree of contraction of these fibers can be regulated. Most of the vasomotor nerves are vasoconstrictor. When they are stimulated, contraction of the Most of the vasomotor nerves are vasoconstrictor. When they are stimulated, contraction of the circular muscle occurs and vasoconstriction ensues. When the stimulation ceases, the muscle circular muscle occurs and vasoconstriction ensues. When the stimulation ceases, the muscle fibers relax and become stretched by the pressure of the blood in the lumen, so the fibers relax and become stretched by the pressure of the blood in the lumen, so the vasodilatation occurs. This vasodilatation is therefore passively produced, by cutting off all vasodilatation occurs. This vasodilatation is therefore passively produced, by cutting off all impulses passing along the vasoconstrictor nerves, as there is a tonic discharge in these impulses passing along the vasoconstrictor nerves, as there is a tonic discharge in these vasoconstrictor adrenergic fibers. In addition to these vasoconstrictor fibers, the skeletal blood vasoconstrictor adrenergic fibers. In addition to these vasoconstrictor fibers, the skeletal blood vessels are innervated by vasodilator fibers which are cholinergic. But vasodilatation can also be vessels are innervated by vasodilator fibers which are cholinergic. But vasodilatation can also be produced in a more active manner, by actually stimulating certain nerves. These vasodilator produced in a more active manner, by actually stimulating certain nerves. These vasodilator nerves are much less numerous than the vasoconstrictor, and their existence was established nerves are much less numerous than the vasoconstrictor, and their existence was established some time after that of the latter. They probably act by inhibiting and causing still further some time after that of the latter. They probably act by inhibiting and causing still further relaxation of the circular muscle, for there are no specially disposed muscle fibers which could, relaxation of the circular muscle, for there are no specially disposed muscle fibers which could, by their contraction, actively dilate the artery. The obvious arrangement for vasodilator fibers by their contraction, actively dilate the artery. The obvious arrangement for vasodilator fibers would be a radial one, the fibers passing from the outer circumference of the vessel towards the would be a radial one, the fibers passing from the outer circumference of the vessel towards the tunica intima; but as has already been pointed out, there are no radial fibers present. An tunica intima; but as has already been pointed out, there are no radial fibers present. An instructive comparison may be made with the pupil, where it is also necessary to be able to instructive comparison may be made with the pupil, where it is also necessary to be able to enlarge or to narrow a circular aperture. In the pupil there is no completely enclosed fluid under enlarge or to narrow a circular aperture. In the pupil there is no completely enclosed fluid under pressure to act as a dilator, and therefore two sets of muscle fibers are required, circular to pressure to act as a dilator, and therefore two sets of muscle fibers are required, circular to constrict, and a radial to dilate. The radial fibers may be for the most part elastic and not constrict, and a radial to dilate. The radial fibers may be for the most part elastic and not muscular, but this does not invalidate the comparison with the arteries, in which no radially muscular, but this does not invalidate the comparison with the arteries, in which no radially arranged dilator elements are needed, since their place is taken by the blood pressure which arranged dilator elements are needed, since their place is taken by the blood pressure which provides a dilating force form within. provides a dilating force form within.

Changes after injury to vessel wall:Changes after injury to vessel wall:

The presence of elastic tissue determines some of the The presence of elastic tissue determines some of the changes which take place in an artery after injury. if an changes which take place in an artery after injury. if an artery of completely severed the cut ends usually retract, artery of completely severed the cut ends usually retract, sometimes for a considerable distance. This can be sometimes for a considerable distance. This can be shown experimentally in animals by measuring a length shown experimentally in animals by measuring a length of an artery in situ, and then removing it, when it may of an artery in situ, and then removing it, when it may shorten by as much as 40 per cent. If an artery is only shorten by as much as 40 per cent. If an artery is only partly severed, the elastic tissue retracts from the edges partly severed, the elastic tissue retracts from the edges of the cut, which is thereby enlarged and kept of the cut, which is thereby enlarged and kept open-‘button-holed’ open-‘button-holed’

ANASTOMOSIS AND COLLATERAL CIRCULATIONANASTOMOSIS AND COLLATERAL CIRCULATION When an arterial trunk gives off successive branches, each of these through When an arterial trunk gives off successive branches, each of these through

its numerous arterioles and capillaries supplies blood to a mass of tissue its numerous arterioles and capillaries supplies blood to a mass of tissue which is termed its vascular area or territory. As a rule, the terminal capillary which is termed its vascular area or territory. As a rule, the terminal capillary network of one artery communicates freely with that of an adjacent artery. network of one artery communicates freely with that of an adjacent artery. Such a communication is anastomoses. If a main arterial trunk Such a communication is anastomoses. If a main arterial trunk A A gives gives origin to two lateral branches, origin to two lateral branches, BB and and CC, whose arterioles or capillaries , whose arterioles or capillaries communicate freely with one another, then if communicate freely with one another, then if AA is occluded at any point is occluded at any point between the origin of these two branches, some blood can still reach the between the origin of these two branches, some blood can still reach the region beyond the obstruction via the anastomoses between region beyond the obstruction via the anastomoses between B B and C. The and C. The flow of blood through the anastomoses is now termed a collateral flow of blood through the anastomoses is now termed a collateral circulation. The amount of blood flowing through the anastomoses may at circulation. The amount of blood flowing through the anastomoses may at first be only small, but if it is enough to keep alive the tissue originally first be only small, but if it is enough to keep alive the tissue originally supplied by supplied by AA, the collateral circulation will usually undergo progressive , the collateral circulation will usually undergo progressive enlargement until finally it transmits as much blood as formerly was enlargement until finally it transmits as much blood as formerly was conveyed by the occluded vessel. conveyed by the occluded vessel.

In the absence of any communication whatever between In the absence of any communication whatever between BB and and C,C, occlusion of occlusion of AA wound result in the complete cessation of blood flow to its wound result in the complete cessation of blood flow to its vascular territory, which would then die and become gangrenous. An artery vascular territory, which would then die and become gangrenous. An artery supplying a mass of tissue without any anastomoses with adjacent vascular supplying a mass of tissue without any anastomoses with adjacent vascular territories, or with anastomoses so poor as not to be able to maintain an territories, or with anastomoses so poor as not to be able to maintain an adequate supply of blood to the affected tissue if the artery is obstructed, is adequate supply of blood to the affected tissue if the artery is obstructed, is an end-artery, in the former instance anatomical, in the latter functionalan end-artery, in the former instance anatomical, in the latter functional

GROWTH OF BLOOD VESSELSGROWTH OF BLOOD VESSELS General considerations:General considerations:

Blood vessels are capable of proliferation throughout life, though not so obviously in the adult as Blood vessels are capable of proliferation throughout life, though not so obviously in the adult as in the embryo, or during childhood and adolescence, when body growth is proceeding actively. In in the embryo, or during childhood and adolescence, when body growth is proceeding actively. In the adult there is always a need, in some regions more than others, for the formation of new the adult there is always a need, in some regions more than others, for the formation of new capillaries to replace those damaged by normal wear and tear; but the process is more in capillaries to replace those damaged by normal wear and tear; but the process is more in evidence in the tissue repair which follows the healing of wounds or of inflammation. A part from evidence in the tissue repair which follows the healing of wounds or of inflammation. A part from proliferation, capillaries may also enlarge and acquire a secondary coat, for example, when a proliferation, capillaries may also enlarge and acquire a secondary coat, for example, when a collateral circulation expends from a capillary network to arteries of appreciable size. There is collateral circulation expends from a capillary network to arteries of appreciable size. There is also convincing evidence that additional arterio-venous anastomoses may readily develop, also convincing evidence that additional arterio-venous anastomoses may readily develop, though in response to what stimulus this occurs is not known. though in response to what stimulus this occurs is not known.

Growth in the adult :Growth in the adult :Multiplication of vessels, as distinct from increase in size, occurs only in capillaries, by a Multiplication of vessels, as distinct from increase in size, occurs only in capillaries, by a characteristic process of sprouting. Solid buds grow out of pre-existing capillaries, usually from characteristic process of sprouting. Solid buds grow out of pre-existing capillaries, usually from the summit of a loop ; and as the growing tip extends the elongating and perhaps branching the summit of a loop ; and as the growing tip extends the elongating and perhaps branching vessel becomes hollow, and its lumen continuous with that of the parent and other vessels. vessel becomes hollow, and its lumen continuous with that of the parent and other vessels. Adjacent capillary sprouts fuse with one another and give rise to a network. In the healing of Adjacent capillary sprouts fuse with one another and give rise to a network. In the healing of wounds the growth of capillaries is associated with the multiplication of per capillary fibroblasts, wounds the growth of capillaries is associated with the multiplication of per capillary fibroblasts, whose activity results in the formation of collagen fibers and the appearance of scar tissue. whose activity results in the formation of collagen fibers and the appearance of scar tissue. The process of capillary growth has been carefully observed, over long periods, in the ear of the The process of capillary growth has been carefully observed, over long periods, in the ear of the rabbit during life. Such observations show that regressive as well as growth changes can occur in rabbit during life. Such observations show that regressive as well as growth changes can occur in capillaries, and that when they are not in active use for any length of time their lumen becomes capillaries, and that when they are not in active use for any length of time their lumen becomes narrowed and obliterated; the solid cellular strand thus formed usually disappears. narrowed and obliterated; the solid cellular strand thus formed usually disappears. Capillaries can enlarge and acquire a secondary coat, developing into arteries or veins according Capillaries can enlarge and acquire a secondary coat, developing into arteries or veins according to the composition of this coat. It is this property of capillaries which is responsible for the to the composition of this coat. It is this property of capillaries which is responsible for the formation of large blood vessels out of a capillary anastomoses, when a collateral circulation is formation of large blood vessels out of a capillary anastomoses, when a collateral circulation is becoming established. New arteries and veins are always laid down in the first place as becoming established. New arteries and veins are always laid down in the first place as capillaries. It is not altogether clear from what tissue elements the secondary coat is derived, capillaries. It is not altogether clear from what tissue elements the secondary coat is derived, when it forms around the primary endothelial tube; it is probable that the primitive adventitial cells when it forms around the primary endothelial tube; it is probable that the primitive adventitial cells play in important part in the process. play in important part in the process.

EXAMINATION OF LIVING BLOOD VESSELS:EXAMINATION OF LIVING BLOOD VESSELS: Arteries:Arteries:

The pulsation of many arteries may be felt, and if they are near the surface The pulsation of many arteries may be felt, and if they are near the surface may also be seen. In the topographical section mention will be made of may also be seen. In the topographical section mention will be made of some of the situations in which individual arteries may be identified. With a some of the situations in which individual arteries may be identified. With a little care even small arteries may be detected, for example, the digital little care even small arteries may be detected, for example, the digital arteries near the base of the finger, on either side of the proximal phalanx, arteries near the base of the finger, on either side of the proximal phalanx, or the superficial palmer artery in front of the thenar eminence. or the superficial palmer artery in front of the thenar eminence.

Capillaries:Capillaries:The capillaries of the skin may be observed with the aid of a microscope, if The capillaries of the skin may be observed with the aid of a microscope, if the epidermis is first cleared and rendered more or less transparent with the epidermis is first cleared and rendered more or less transparent with cedar-wood oil, and a strong beam of light focused on it. The most cedar-wood oil, and a strong beam of light focused on it. The most convenient situation for observing capillaries is the nail bed, where smaller convenient situation for observing capillaries is the nail bed, where smaller arterioles and venules can also occasionally be seen. arterioles and venules can also occasionally be seen.

X-ray examination of blood vessels. [Angiography] :X-ray examination of blood vessels. [Angiography] :In the thorax, simple X-ray examination is sufficient to demonstrate the heart In the thorax, simple X-ray examination is sufficient to demonstrate the heart and some of the larger blood vessels, for example, the arch of the aorta or and some of the larger blood vessels, for example, the arch of the aorta or the branches of the pulmonary artery, as they radiate from the root of the the branches of the pulmonary artery, as they radiate from the root of the lung. These vascular shadows stand out because of the contrast afforded lung. These vascular shadows stand out because of the contrast afforded by the air-containing lung tissue surrounding them. In other parts of the by the air-containing lung tissue surrounding them. In other parts of the body, however, healthy blood vessels are not so readily visible on body, however, healthy blood vessels are not so readily visible on radiographic examination, and only become so it a radio-opaque substance radiographic examination, and only become so it a radio-opaque substance is injected into them; this procedure is known as angiography. is injected into them; this procedure is known as angiography. Arteries of the body can be subdivided into those of pulmonary and those of Arteries of the body can be subdivided into those of pulmonary and those of systemic circulation. systemic circulation.

ARCH OF AORTA AND its BRANCHESARCH OF AORTA AND its BRANCHES It extends mainly in the anterioposterior direction but also inclines to the left. It extends mainly in the anterioposterior direction but also inclines to the left.

At first it is in the front of the superior mediastinum, but it then passes back At first it is in the front of the superior mediastinum, but it then passes back to the back of superior mediastinum reaches the left side of the body of 4th to the back of superior mediastinum reaches the left side of the body of 4th thoracic vertebra, where it continues as descending thoracic aorta. thoracic vertebra, where it continues as descending thoracic aorta.

From before backwards the aortic arch gives origin to the brachiocephalic, From before backwards the aortic arch gives origin to the brachiocephalic, left common carotid and left common carotid and left subclavian arteries. left common carotid and left common carotid and left subclavian arteries.

The left brachiocephalic vein and thymus gland lie anterior to the common The left brachiocephalic vein and thymus gland lie anterior to the common cement of these 3 arteries and to the summit of the aortic arch. cement of these 3 arteries and to the summit of the aortic arch.

The arch of aorta and its branches not frequently provide excellent The arch of aorta and its branches not frequently provide excellent examples of arterial variations. For ex: the arch of the aorta is normally examples of arterial variations. For ex: the arch of the aorta is normally developed from the 4th. Left brachial artery, but it may occasionally develop developed from the 4th. Left brachial artery, but it may occasionally develop form the fourth right, as normally happens in birds, in which cases the arch form the fourth right, as normally happens in birds, in which cases the arch passes to the right of the vertebral column.passes to the right of the vertebral column.

Variation in branches :Variation in branches :While minor variation in the origin of the vessels arising from the aortic arch While minor variation in the origin of the vessels arising from the aortic arch are relatively common, they are also of little surgical importance. are relatively common, they are also of little surgical importance. With the exception of right andWith the exception of right and double aortic arch and anomalies of double aortic arch and anomalies of subclavian arteries.. subclavian arteries..

BRACHIOCEPHALIC ARTERYBRACHIOCEPHALIC ARTERY COURSE AND SURFACE ANATOMY :COURSE AND SURFACE ANATOMY : The brachiocephalic trunk arises from the arch of aorta behind the The brachiocephalic trunk arises from the arch of aorta behind the

middle of manubrium sterni. It is 3.5 to 5 cm long and runs middle of manubrium sterni. It is 3.5 to 5 cm long and runs upwards, backward and to the right from the superior mediastinum upwards, backward and to the right from the superior mediastinum into the root of the neck. It ends at the level of the upper part of Rt into the root of the neck. It ends at the level of the upper part of Rt sternoclavicular joint by dividing into right subclavian and common sternoclavicular joint by dividing into right subclavian and common carotid arteries. carotid arteries.

Anteriorly the left brachiocephalic vein crosses between it and Anteriorly the left brachiocephalic vein crosses between it and thymus. thymus.

At higher levels the sternothyroid muscle separates it from At higher levels the sternothyroid muscle separates it from sternohyoid and sternoclavicular joint. On its left side left common sternohyoid and sternoclavicular joint. On its left side left common carotid artery originates and at a higher level trachea is in contact carotid artery originates and at a higher level trachea is in contact with it. with it.

Branches:Branches:As well as its two terminal branches the brachiocephalic trunk may As well as its two terminal branches the brachiocephalic trunk may give off the thyroidea Ima which runs on the front of trachea to the give off the thyroidea Ima which runs on the front of trachea to the thyroid thyroid

COMMON CAROTID ARTERIESCOMMON CAROTID ARTERIES SURFACE ANATOMY:SURFACE ANATOMY: A line from a point just below and A line from a point just below and

to the left of the centre of to the left of the centre of manubrium sterni to the manubrium sterni to the sternoclavicular joint – represents sternoclavicular joint – represents thoracic portion. thoracic portion.

The cervical portion of the left The cervical portion of the left artery and all of the right is artery and all of the right is indicated by a line drawn from the indicated by a line drawn from the appropriate sternoclavicular joint appropriate sternoclavicular joint to a point 1 cm behind the superior to a point 1 cm behind the superior horn of thyroid cartilage. horn of thyroid cartilage.

The left common carotid artery is The left common carotid artery is intermediate in position among the intermediate in position among the three branches of the arch of three branches of the arch of aorta. It ascends upwards behind aorta. It ascends upwards behind the manubrium sterni to the level the manubrium sterni to the level of the left sternoclavicular of the left sternoclavicular articulation from where it is articulation from where it is continued to the neck. Thus the continued to the neck. Thus the left subclavian artery can be left subclavian artery can be divided into thoraic and cervical divided into thoraic and cervical part. part.

COMMON CAROTID ARTERIESCOMMON CAROTID ARTERIES

Thoraic part:Thoraic part: Course and relation Course and relation Anteriorly – related to back of manubrium sterni being separated by Anteriorly – related to back of manubrium sterni being separated by

sternohyoid and sternothyroid muscles. sternohyoid and sternothyroid muscles. Close to its origin it is crossed in front by the left branchiocephalic Close to its origin it is crossed in front by the left branchiocephalic

(innominate) vein. (innominate) vein. Posteriorly: It is related to trachea, left edge of oesophagus, thoraic Posteriorly: It is related to trachea, left edge of oesophagus, thoraic

duct and the left recurrent laryngerial nerve. duct and the left recurrent laryngerial nerve. On right side – Related to brachiocephalic (innominate) artery in On right side – Related to brachiocephalic (innominate) artery in

lower part and trachea in its upper part.lower part and trachea in its upper part. On left side – It is related to phremic nerve. The left subclavian On left side – It is related to phremic nerve. The left subclavian

artery the left lung and the pleura. artery the left lung and the pleura. It does not provide any branch in the thorax. It does not provide any branch in the thorax.


CERVICAL PART :CERVICAL PART :The common carotid artery enters the neck behind the sternoclavicular articulation The common carotid artery enters the neck behind the sternoclavicular articulation and ascends upwards and backwards under the cover of anterior margin. and ascends upwards and backwards under the cover of anterior margin. sternomastoid up to the upper border of thyroid cartilage. sternomastoid up to the upper border of thyroid cartilage.

Relations :Relations :Posteriorly – related to anterior tubercles of the transverse processes of the lower, Posteriorly – related to anterior tubercles of the transverse processes of the lower, four cervical vertebrae and the origins of the scalenus anterior and longus cervicis four cervical vertebrae and the origins of the scalenus anterior and longus cervicis and capitis muscle. At the root of the neck it is related posteriorly to the 1st portion of and capitis muscle. At the root of the neck it is related posteriorly to the 1st portion of vertebral artery and the origin of inferior thyroid artery. vertebral artery and the origin of inferior thyroid artery.

Anteriorly :Anteriorly :Covered by skin superfacial fascia, platsyma and the deep fascia is overlapped, by Covered by skin superfacial fascia, platsyma and the deep fascia is overlapped, by the anterior margin of sternomastoid muscle. In the lower part of the neck the inferior the anterior margin of sternomastoid muscle. In the lower part of the neck the inferior belly of omohyoid sternothyroid and sternohyoid intervene between it. belly of omohyoid sternothyroid and sternohyoid intervene between it.

Laterally :Laterally :It is covered by sternomastoid being separated by carotid sheath. It is covered by sternomastoid being separated by carotid sheath.

Medially :Medially :It is related to the pharynx larynx, trachea oesophagus and the thyroid gland. It is related to the pharynx larynx, trachea oesophagus and the thyroid gland.

Except its terminal branches (external and internal carotid arteries) usually it does not Except its terminal branches (external and internal carotid arteries) usually it does not provide any branches in the neck. provide any branches in the neck.

It it’s point of bifurcation it usually represents a dilation known as “carotid sinus”. This It it’s point of bifurcation it usually represents a dilation known as “carotid sinus”. This is due to thickness of tunica media with proportionate thickness of the tumica is due to thickness of tunica media with proportionate thickness of the tumica adventia. The carotid sinus is richly supplied with sympathetic and parasympathetic adventia. The carotid sinus is richly supplied with sympathetic and parasympathetic (glossophrengal) nerves and is concerned in regulation of blood pressure in the (glossophrengal) nerves and is concerned in regulation of blood pressure in the cerebral arteries cerebral arteries


DEVELOPMENT :DEVELOPMENT :The third aortic arch together with the The third aortic arch together with the persisting dorsal aorta cranial to it forms the persisting dorsal aorta cranial to it forms the common and internal carotid arteries. common and internal carotid arteries.

ANOMALIES :ANOMALIES : When the innominate stem is absorbed into When the innominate stem is absorbed into the aortic arch the right common carotid the aortic arch the right common carotid artery arises from the arch of aorta and artery arises from the arch of aorta and forms the second branch from the right side forms the second branch from the right side (1st being RT subclavian). (1st being RT subclavian). When the right 4th aortic arch is obliterated When the right 4th aortic arch is obliterated the right subclavian arises from the the right subclavian arises from the descending aorta, and the right common descending aorta, and the right common carotid in this case forms the 1st branch of carotid in this case forms the 1st branch of the arch of aorta. the arch of aorta. The common carotid may fail to divide or it The common carotid may fail to divide or it may divide either at a higher or at a lower may divide either at a higher or at a lower level. When it odes not divide the branches level. When it odes not divide the branches which usually arise from the external carotid which usually arise from the external carotid will arise from it will arise from it

APPLIED SURGICAL ANATOMY (CLINICAL RELIVANCE)APPLIED SURGICAL ANATOMY (CLINICAL RELIVANCE) CAROTID ENDARTERECTOMY:CAROTID ENDARTERECTOMY:

Atheroscleraotic thickening of the intima of internal carotid artery, which obstructs blood flow can Atheroscleraotic thickening of the intima of internal carotid artery, which obstructs blood flow can be observed in Doppler color study. be observed in Doppler color study. A Doppler in a diagnostic instrument that emits an ultrasonic beam that reflects from moving A Doppler in a diagnostic instrument that emits an ultrasonic beam that reflects from moving structure partial occlusion of the internal carotid may also cause a transient ischemic attack – structure partial occlusion of the internal carotid may also cause a transient ischemic attack – sudden focal loss of neurological function. (ex: dizziness and disorientation). That appear within sudden focal loss of neurological function. (ex: dizziness and disorientation). That appear within 24 hours. Arterial occlusion may also cause a minor stroke – loss of neurological function such 24 hours. Arterial occlusion may also cause a minor stroke – loss of neurological function such as weakness or sensory loss on one side of the body that exceeds 24 hour but disappear within as weakness or sensory loss on one side of the body that exceeds 24 hour but disappear within 3 weeks. They symptoms resulting from obstruction of blood flow depend on the degree of 3 weeks. They symptoms resulting from obstruction of blood flow depend on the degree of obstruction and the amount of collateral blood flow to the brain and structures in the orbit from obstruction and the amount of collateral blood flow to the brain and structures in the orbit from other arteries. other arteries. Carotid stenosis (narrowing) in healthy patients can be relieved by opening the artery and Carotid stenosis (narrowing) in healthy patients can be relieved by opening the artery and stripping off the atherosclerofic plaque with the intima. The common site of carotid, stripping off the atherosclerofic plaque with the intima. The common site of carotid, endarterectomy is the internal carotid artery. Just superior to the origin after the operation endarterectomy is the internal carotid artery. Just superior to the origin after the operation administered drug inhibit clot formation in the operated area until the endothelium has re grown. administered drug inhibit clot formation in the operated area until the endothelium has re grown.

CAROTID PULSE:CAROTID PULSE:The carotid pulse (neck) is easily felt by palpating the common carotid artery in the side of the The carotid pulse (neck) is easily felt by palpating the common carotid artery in the side of the neck. Where it lies in the groove between trachea and infrahyoid muscle. It is usually easily neck. Where it lies in the groove between trachea and infrahyoid muscle. It is usually easily palpated just deep to the anterior border of sternocledomastoid muscle, at the level of superior palpated just deep to the anterior border of sternocledomastoid muscle, at the level of superior border of thyroid cartilage. It is routinely checked during CARDIOPULMONARY border of thyroid cartilage. It is routinely checked during CARDIOPULMONARY RESUSCITATION. Absence of carotid pulse indicates ceratoid arrest. RESUSCITATION. Absence of carotid pulse indicates ceratoid arrest.

CAROTID ARTERY PALPATION :CAROTID ARTERY PALPATION :External pressure on the carotid artery in people with carotid sinus hypersensitivity may cause. External pressure on the carotid artery in people with carotid sinus hypersensitivity may cause. Slowing of heart rate, fall in blood pressure and cardiac ischemia with fainting. Slowing of heart rate, fall in blood pressure and cardiac ischemia with fainting. In al forms of syncope symptoms result from sudden and critical decrease in cerebral perfusion. In al forms of syncope symptoms result from sudden and critical decrease in cerebral perfusion. Consequently this method of taking the pulse in not recommended for cardiac patients who are Consequently this method of taking the pulse in not recommended for cardiac patients who are participating in cardiac rehabilitation programs. Because various types of vascular disease affect participating in cardiac rehabilitation programs. Because various types of vascular disease affect the sensitivity of the carotid sinus, the radial pulse at the resist is most commonly checked. the sensitivity of the carotid sinus, the radial pulse at the resist is most commonly checked.

THE EXTERNAL CAROTID ARTERYTHE EXTERNAL CAROTID ARTERY

Branches of the external carotid artery :Branches of the external carotid artery :1.1. Superior thyroid Superior thyroid 2.2. Ascending pharyngealAscending pharyngeal3.3. LingualLingual4.4. Facial Facial 5.5. Occipital Occipital 6.6. Posterior auricular Posterior auricular 7.7. Superficial temporalSuperficial temporal8.8. Maxillary. Maxillary. DevelopmentDevelopment : The external carotid artery arises as a branch : The external carotid artery arises as a branch

budding off from the ventral root of the third aortic arch. budding off from the ventral root of the third aortic arch. Anomalies :Anomalies : As already stated there may be complete absence of As already stated there may be complete absence of

the external carotid artery or occasionally it may arise directly from the external carotid artery or occasionally it may arise directly from the arch of the aorta. the arch of the aorta.

Superior thyroid arterySuperior thyroid artery : : It arises from the front of the external carotid artery immediately It arises from the front of the external carotid artery immediately

below the greater cornu of the hyoid bone. At first it lies under cover below the greater cornu of the hyoid bone. At first it lies under cover of the anterior border of the sternocleidomastoid muscle and then it of the anterior border of the sternocleidomastoid muscle and then it becomes superficial being covered only by the skin, superficial becomes superficial being covered only by the skin, superficial fascia, platysma and the deep fascia and then again it becomes fascia, platysma and the deep fascia and then again it becomes deep as it descends downwards beneath the omohyoid (superior deep as it descends downwards beneath the omohyoid (superior belly), sternohyoid and sternothyroid muscles and finally reaching belly), sternohyoid and sternothyroid muscles and finally reaching the upper pole of the thyroid gland it breaks up into the terminal the upper pole of the thyroid gland it breaks up into the terminal branches anterior and posterior. Medially it is related to the inferior branches anterior and posterior. Medially it is related to the inferior constrictor muscle of the pharynx and the external laryngeal nerve. constrictor muscle of the pharynx and the external laryngeal nerve.

The anterior branch runs along the medial border of the The anterior branch runs along the medial border of the upper poly of the thyroid gland and supplies the superficial surface upper poly of the thyroid gland and supplies the superficial surface of the thyroid and provides an anastomosing branch which runs of the thyroid and provides an anastomosing branch which runs along and upper border of the isthmus and end by anastomosing along and upper border of the isthmus and end by anastomosing with the fellow of the opposite side. with the fellow of the opposite side.

The posterior branch runs along the posterior border of the The posterior branch runs along the posterior border of the gland and supplies the medial and the posterior surfaces and finally gland and supplies the medial and the posterior surfaces and finally ends by anastomosing with the inferior thyroid artery. ends by anastomosing with the inferior thyroid artery.

Superior thyroid arterySuperior thyroid artery : :

Branches :Branches :1.1. Infrahyoid Infrahyoid 2.2. Sternomastoid Sternomastoid 3.3. Superior laryngeal Superior laryngeal 4.4. Cricothyroid Cricothyroid 5.5. Terminal glandular Terminal glandular

Superior thyroid arterySuperior thyroid artery : : Infrahyoid branch :Infrahyoid branch : This is a small branch arising from the superior This is a small branch arising from the superior

thyroid artery and runs forwards along the lower border of the hyoid thyroid artery and runs forwards along the lower border of the hyoid bone and ends by anastomosing with the fellow of its opposite side. bone and ends by anastomosing with the fellow of its opposite side.

Sternomastoid branch :Sternomastoid branch : The sternomastoid branch of the superior The sternomastoid branch of the superior thyroid artier runs downwards and laterally in front of the carotid thyroid artier runs downwards and laterally in front of the carotid sheath and soon enters into the sternomastoid muscle. This artery sheath and soon enters into the sternomastoid muscle. This artery may arise from the external carotid artery. may arise from the external carotid artery.

Superior laryngeal branch :Superior laryngeal branch : The superior laryngeal branch of the The superior laryngeal branch of the superior thyroid artery is larger than the preceding two arteries and superior thyroid artery is larger than the preceding two arteries and runs upwards and medially behind thyrohyoid muscle and runs upwards and medially behind thyrohyoid muscle and accompanying the internal laryngeal nerve it pierces the hyothyroid accompanying the internal laryngeal nerve it pierces the hyothyroid membrane and lies below the internal laryngeal nerve. It supplies membrane and lies below the internal laryngeal nerve. It supplies the muscles, mucous membranes and glands of the larynx and ends the muscles, mucous membranes and glands of the larynx and ends by anastomosing with the fellow of its opposite side and also with by anastomosing with the fellow of its opposite side and also with the inferior laryngeal branch of the inferior thyroid artery. the inferior laryngeal branch of the inferior thyroid artery.

Cricothyroid branch :Cricothyroid branch : It is a transverse branch from the superior It is a transverse branch from the superior thyroid artery and runs transversely across the upper border of the thyroid artery and runs transversely across the upper border of the cricothyroid membrane and ends by anastomosing with the artery of cricothyroid membrane and ends by anastomosing with the artery of the opposite side the opposite side

Terminal glandular branch :Terminal glandular branch : The terminal glandular branches are The terminal glandular branches are anterior and posterior and have been described with the main artery anterior and posterior and have been described with the main artery

Lingual arteryLingual artery : : First part of the lingual artery :First part of the lingual artery : The first The first

part of lingual artery lies in the carotid part of lingual artery lies in the carotid triangle and extends from its origin to the triangle and extends from its origin to the posterior border of the hyoglossus muscle; posterior border of the hyoglossus muscle; at first it runs upwards, forwards and at first it runs upwards, forwards and medially and then forming a loop descends medially and then forming a loop descends downwards to the greater cornu of the hyoid downwards to the greater cornu of the hyoid bone and reaches the posterior border of bone and reaches the posterior border of the hyoglossus muscle; in this part of its the hyoglossus muscle; in this part of its course it is superficial, being covered only course it is superficial, being covered only by the skin, superficial fascia, platysma and by the skin, superficial fascia, platysma and the deep fascia; it lies on the middle the deep fascia; it lies on the middle constrictor muscle of the pharynx. The loop constrictor muscle of the pharynx. The loop which is the characteristic of the artery is which is the characteristic of the artery is crosses by the hypoglossal nerve. crosses by the hypoglossal nerve.

Second part of the lingual artery :Second part of the lingual artery : The The second part of the lingual artery lies deep to second part of the lingual artery lies deep to the hyoglossus muscle. In this part of its the hyoglossus muscle. In this part of its course it runs along the upper border of the course it runs along the upper border of the hyoid bone and is covered by the hyoid bone and is covered by the hyoglossus muscle, the tendon of the hyoglossus muscle, the tendon of the digastric, stylohyoid and the posterior part of digastric, stylohyoid and the posterior part of the mylohyoid muscle and the lower part of the mylohyoid muscle and the lower part of the submandibular gland. It is separated the submandibular gland. It is separated from the hypoglossal nerve and its venae from the hypoglossal nerve and its venae commitans by the hyoglossus muscle. It lies commitans by the hyoglossus muscle. It lies on the middle constrictor muscle of the on the middle constrictor muscle of the pharynx. pharynx.

Lingual arteryLingual artery : : 33rdrd part of the lingual artery : part of the lingual artery : The third part of the lingual artery The third part of the lingual artery

extends from the anterior border of the extends from the anterior border of the hyoglossus muscle to the tip of the hyoglossus muscle to the tip of the tongue. At the anterior border of the tongue. At the anterior border of the hyoglossus muscle the lingual artery hyoglossus muscle the lingual artery gives out its sublingual branch and gives out its sublingual branch and then is continued to the under surface then is continued to the under surface of the tongue as the arteria profunda of the tongue as the arteria profunda linguae. At first it ascends vertically linguae. At first it ascends vertically upwards and then runs forwards upwards and then runs forwards vertically upwards and then runs vertically upwards and then runs forwards to the under surface of the forwards to the under surface of the tongue on the side of the frenulum and tongue on the side of the frenulum and finally reaches the tip of the tongue finally reaches the tip of the tongue where it ends by anastomosing with where it ends by anastomosing with the fellow of its opposite side. In this the fellow of its opposite side. In this part of its course it is accompanied by part of its course it is accompanied by the lingual nerve, and the the lingual nerve, and the genioglossus muscles lies on its genioglossus muscles lies on its medial side. Latterly it is related to the medial side. Latterly it is related to the lingitudinalis linguae inferior and lingitudinalis linguae inferior and inferiorly is covered only by the inferiorly is covered only by the mucous membrane of the tongue. mucous membrane of the tongue.

Branches :Branches : Suprayhoid Suprayhoid Rami dorsales linguaeRami dorsales linguae Sublingual Sublingual Arteria profunda linguae. Arteria profunda linguae.

FACIAL ARTERYFACIAL ARTERY CERVICAL PART OF THE FACIAL ARTERY :CERVICAL PART OF THE FACIAL ARTERY : Course :Course : In the neck, the facial artery arises from In the neck, the facial artery arises from

the anterior aspect of the external carotid artery in the anterior aspect of the external carotid artery in the carotid triangle a little higher than the lingual the carotid triangle a little higher than the lingual artery and immediately above the greater cornu of artery and immediately above the greater cornu of the hyoid bone. From its origin it ascends vertically the hyoid bone. From its origin it ascends vertically upwards to the angle of the mandible and then upwards to the angle of the mandible and then turns downwards forming a loop and descends in turns downwards forming a loop and descends in the groove on the posterior part of the the groove on the posterior part of the submandibular gland and then it passes forwards submandibular gland and then it passes forwards between the lateral surface of the submandibular between the lateral surface of the submandibular gland and the medial pterygoid muscle and reach gland and the medial pterygoid muscle and reach the lower border of the mandible and finally it the lower border of the mandible and finally it arches over the mandible to enter the face at the arches over the mandible to enter the face at the anterior border of the masseter muscle. anterior border of the masseter muscle.

Relation :Relation : In is course through the neck it is at first In is course through the neck it is at first superficial being covered only by the skin, superficial being covered only by the skin, superficial fascia, platysma and the deep fascia, superficial fascia, platysma and the deep fascia, and opposite the angle of the mandible it becomes and opposite the angle of the mandible it becomes deep by passing beneath the posterior belly of the deep by passing beneath the posterior belly of the digastric and the stylohyoid muscles. Then it lies in digastric and the stylohyoid muscles. Then it lies in the groove on the posterior aspect of the the groove on the posterior aspect of the submandibularsubmandibular gland, and subsequently, it lies gland, and subsequently, it lies between the gland and the medial pterygoid between the gland and the medial pterygoid muscle. Again it mandible to enter into the face. muscle. Again it mandible to enter into the face. Here the (anterior) facial vein lies posterior to it. At Here the (anterior) facial vein lies posterior to it. At first it lies on the middle constrictor muscle of the first it lies on the middle constrictor muscle of the pharynx, and higher up, opposite the angle of the pharynx, and higher up, opposite the angle of the mandible lies on the superior constrictor muscle or mandible lies on the superior constrictor muscle or it may ascent further up to lie on the styloglossus it may ascent further up to lie on the styloglossus muscle and in this situation it is separated from the muscle and in this situation it is separated from the palatine tonsil by the superior constrictor and the palatine tonsil by the superior constrictor and the styloglossus muscles. Occasionally it may be styloglossus muscles. Occasionally it may be crossed by the hypoglossal nerve. crossed by the hypoglossal nerve.

FACIAL ARTERYFACIAL ARTERY FACIAL PART OF THE FACIAL ARTERY :FACIAL PART OF THE FACIAL ARTERY : Course :Course : The facial artery enters the face at The facial artery enters the face at

the anterior border of the masseter muscle the anterior border of the masseter muscle and ascends upwards and forwards across and ascends upwards and forwards across the cheek to reach the angle of the mouth the cheek to reach the angle of the mouth and then ascends further up along the side and then ascends further up along the side of the nose to reach the medial palpebral of the nose to reach the medial palpebral commissure where it ends by anastomosing commissure where it ends by anastomosing with the dorsal nasal branch of the with the dorsal nasal branch of the ophthalmic artery. ophthalmic artery.

Relation :Relation : Opposite the anterior border of Opposite the anterior border of the masseter it is superficial and lies under the masseter it is superficial and lies under cover of the skin, superficial fascia and the cover of the skin, superficial fascia and the platysma. In its course through the face it is platysma. In its course through the face it is covered by the skin, fat of the cheek, and covered by the skin, fat of the cheek, and opposite the angle of the mouth, it lies opposite the angle of the mouth, it lies under the risorius and the zygomaticus under the risorius and the zygomaticus major ; opposite the medial palpebral major ; opposite the medial palpebral commissure it is hidden by the fibres of the commissure it is hidden by the fibres of the levator labii superioris alaeque nasi. It lies levator labii superioris alaeque nasi. It lies successively upon anguli oris and the successively upon anguli oris and the levator labii superioris alaeque nasi. The levator labii superioris alaeque nasi. The (anterior) facial vein lies posterior to it (anterior) facial vein lies posterior to it opposite the medial palpebral commissure opposite the medial palpebral commissure and then is separated from it by a and then is separated from it by a considerable distance and opposite the considerable distance and opposite the anterior border of the masseter, it again anterior border of the masseter, it again comes into intimate relation with the artery comes into intimate relation with the artery and lies immediately posterior to it. and lies immediately posterior to it.

FACIAL ARTERYFACIAL ARTERY

Branches :Branches : Cervical part :Cervical part : Ascending palatineAscending palatine Tonsillar Tonsillar Glandular Glandular Submental Submental Facial part :Facial part : Superior labial Superior labial Inferior labial Inferior labial Lateral nasal. Lateral nasal.

Occipital arteryOccipital artery : : Course :Course : The occipital artery arises from the The occipital artery arises from the

external carotid artery opposite the origin of external carotid artery opposite the origin of the facial artery. It ascends upwards and the facial artery. It ascends upwards and backwards to reach the posterior part of the backwards to reach the posterior part of the scalp where it ends by supplying it. scalp where it ends by supplying it.

Relation :Relation : At first it lies in the carotid only by At first it lies in the carotid only by the skin, superficial fascia, platysma and the skin, superficial fascia, platysma and deep fascia. Then as it runs upwards and deep fascia. Then as it runs upwards and backwards it crosses the internal carotid backwards it crosses the internal carotid artery, the internal jugular vein, the artery, the internal jugular vein, the hypoglossal (which hooks round it), the hypoglossal (which hooks round it), the vagus and the accessory nerves and then vagus and the accessory nerves and then passes under cover of the posterior belly of passes under cover of the posterior belly of the digastric to reach the posterior between the digastric to reach the posterior between the transverse process of the atlas and the the transverse process of the atlas and the mastoid process of the temporal bone. Then mastoid process of the temporal bone. Then it traverses the groove on the mastoid part it traverses the groove on the mastoid part of the temporal plenius capitis, longissimus of the temporal plenius capitis, longissimus capitis and the posterior belly of the capitis and the posterior belly of the digastric. Finally it aponeurotic connection digastric. Finally it aponeurotic connection between the sternomastoid and the between the sternomastoid and the trapezius and then divides into branches trapezius and then divides into branches which pass in the subcutaneous tissue of which pass in the subcutaneous tissue of the scalp and ends by supplying it. In the the scalp and ends by supplying it. In the course upwards and backwards from above course upwards and backwards from above the level of the transverse process of the the level of the transverse process of the atlas to the scalp it lies successively upon atlas to the scalp it lies successively upon the rectus captitis lateralis, obliquus capitis the rectus captitis lateralis, obliquus capitis superior and the semispinalis capitis. Its superior and the semispinalis capitis. Its terminal branches are accompanied by he terminal branches are accompanied by he branches from the greater occipital nerve. branches from the greater occipital nerve.

Occipital artery :Occipital artery :

Branches :Branches :Sternomastoid Sternomastoid Mastoid Mastoid Auricular Auricular Muscular Muscular DescendingDescendingMeningeal Meningeal Occipital (terminal branches Occipital (terminal branches

Ascending pharyngeal artery :Ascending pharyngeal artery : This is the smallest This is the smallest

branch from the external branch from the external carotid artery and arises carotid artery and arises from it just after it origin. from it just after it origin. It is deeply seated and It is deeply seated and runs vertically upwards runs vertically upwards on the longus capitis on the longus capitis muscle to the base of the muscle to the base of the skull and lies in between skull and lies in between the internal carotid artery the internal carotid artery and the side wall of the and the side wall of the pharynx. It is crossed by pharynx. It is crossed by the styloglossus and the the styloglossus and the stylopharygneus. At the stylopharygneus. At the base of the skull it base of the skull it anastomoses with the anastomoses with the ascending palatine ascending palatine branch of the facial branch of the facial artery. artery.

Ascending pharyngeal arteryAscending pharyngeal artery

Branches :Branches : Pharyngeal Pharyngeal Inferior tympanic Inferior tympanic Meningeal Meningeal Pharyngeal branches :Pharyngeal branches : The pharyngeal branches of the ascending The pharyngeal branches of the ascending

pharyngeal artery are two or three in number and they supply the muscles pharyngeal artery are two or three in number and they supply the muscles of the pharynx. One of the branches passes through the gap between the of the pharynx. One of the branches passes through the gap between the upper border of the superior constrictor muscle of the pharynx and the base upper border of the superior constrictor muscle of the pharynx and the base of the skull and accompanying the levator muscle it enters the soft palate. It of the skull and accompanying the levator muscle it enters the soft palate. It may replace the ascending palatine branch of the facial artery. may replace the ascending palatine branch of the facial artery.

Inferior tympanic branch :Inferior tympanic branch : It is a small branch which enters the tympanic It is a small branch which enters the tympanic cavity through the tympanic canaliculus in company with the tympanic cavity through the tympanic canaliculus in company with the tympanic branch of the glossopharyngeal nerve. It supplies the medial wall of the branch of the glossopharyngeal nerve. It supplies the medial wall of the tympanic cavity and ends by anastomosing with the other tympanic arteries. tympanic cavity and ends by anastomosing with the other tympanic arteries.

Meningeal branches :Meningeal branches : They are several small branches which supply the They are several small branches which supply the dura mater. They enter the cranial cavity through the anterior condylar dura mater. They enter the cranial cavity through the anterior condylar canal, jugular foramen and foramen lacerum. canal, jugular foramen and foramen lacerum.

Posterior auricular artery :Posterior auricular artery : It is small branch from the It is small branch from the

external carotid artery external carotid artery and arsis from it as it is and arsis from it as it is crossed by the posterior crossed by the posterior belly of the digastric and belly of the digastric and the stylohyoid muscles. It the stylohyoid muscles. It runs upwards and runs upwards and backwards under cover of backwards under cover of the parotid gland to reach the parotid gland to reach the mastoid process the mastoid process where it ends by dividing where it ends by dividing into auricular and into auricular and occipital branches. occipital branches.

Posterior auricular artery :Posterior auricular artery :

Branches Branches Auricular Auricular Occipital Occipital Stylomastoid Stylomastoid Auricular branch :Auricular branch : It supplies the posterior part of the auricle and It supplies the posterior part of the auricle and

ends by anastomosing with posterior and auricular branches of the ends by anastomosing with posterior and auricular branches of the superficial temporal artery. superficial temporal artery.

Occipital branch :Occipital branch : It passes laterally crossing the mastoid process It passes laterally crossing the mastoid process and reaches the posterior part of the scalp where it ends by and reaches the posterior part of the scalp where it ends by anastomosing with the occipital artery. anastomosing with the occipital artery.

Stylomastoid branch :Stylomastoid branch : The stylomastoid branch of the posterior The stylomastoid branch of the posterior auricular artery enters the stylomastoid foramen and then enters auricular artery enters the stylomastoid foramen and then enters into the tympanic cavity. It supplies the tympanic cavity, the into the tympanic cavity. It supplies the tympanic cavity, the tympanic antrum, the mastoid air cells and the semicircular canals tympanic antrum, the mastoid air cells and the semicircular canals and anastomoses with the superficial petrosal branch of the middle and anastomoses with the superficial petrosal branch of the middle meningeal artery meningeal artery

Superficial temporal arterySuperficial temporal artery It is the smaller terminal branch of It is the smaller terminal branch of

the external carotid artery and the external carotid artery and arises from the same opposite the arises from the same opposite the neck of the mandible within the neck of the mandible within the substance of the parotid gland. It substance of the parotid gland. It then crosses the posterior root of then crosses the posterior root of the zygomatic process and the zygomatic process and ascends vertically upwards under ascends vertically upwards under cover of the auricularis anterior for cover of the auricularis anterior for about 5.0 cm and ends by dividing about 5.0 cm and ends by dividing into the anterior and posterior into the anterior and posterior branches. Within the parotid gland branches. Within the parotid gland it is crossed by the zygomatic and it is crossed by the zygomatic and the temporal branches of the facial the temporal branches of the facial nerve. Outside the parotid gland nerve. Outside the parotid gland the auriculotemporal nerve lies the auriculotemporal nerve lies posterior to it and the temporal posterior to it and the temporal branch of the facial nerve lies branch of the facial nerve lies anterior to it. It gives out the anterior to it. It gives out the following branches: following branches:

Superficial temporal arterySuperficial temporal artery Branches :Branches : Transverse facial Transverse facial Auricular Auricular Zygomatico-orbital Zygomatico-orbital Middle temporal Middle temporal Frontal Frontal Parietal. Parietal. Transverse facial branch :Transverse facial branch : It arises from it from within the parotid gland and crosses It arises from it from within the parotid gland and crosses

superficial to the masseter muscle lying above the parotid duct and supplies the superficial to the masseter muscle lying above the parotid duct and supplies the parotid gland with its ducts, the masseter muscle and the adjacent skin. It parotid gland with its ducts, the masseter muscle and the adjacent skin. It anastomoses with facial infra-orbital, buccal and masseteric arteries. anastomoses with facial infra-orbital, buccal and masseteric arteries.

Auricular branches :Auricular branches : They are distributed to the lobule, the anterior part of the They are distributed to the lobule, the anterior part of the auricle and external auditory meatus and anastomoses with the posterior auricular auricle and external auditory meatus and anastomoses with the posterior auricular artery. artery.

Zygomatico-orbital branch :Zygomatico-orbital branch : It runs along the upper border of the zygomatic arch It runs along the upper border of the zygomatic arch between the two layers of the temporal fascia to the lateral angle of the orbit where it between the two layers of the temporal fascia to the lateral angle of the orbit where it anastomoses with the lacrimal and palpebral branches of the ophthalmic artery. anastomoses with the lacrimal and palpebral branches of the ophthalmic artery.

Middle temporal branch :Middle temporal branch : It arises from the superficial temporal artery above the It arises from the superficial temporal artery above the zygomatic arch and it pierces the temporal fascia, supplies the temporalis muscle and zygomatic arch and it pierces the temporal fascia, supplies the temporalis muscle and ends by anastomosing with the deep auricular branch of the maxillary artery. ends by anastomosing with the deep auricular branch of the maxillary artery.

Frontal branch :Frontal branch : It runs upwards and forwards to the frontal eminence and ends by It runs upwards and forwards to the frontal eminence and ends by anastomosing with the fellow of its opposite side and with the supraorbital and anastomosing with the fellow of its opposite side and with the supraorbital and supratrochlear arteries. It is very tortuous in its course. supratrochlear arteries. It is very tortuous in its course.

Parietal branch :Parietal branch : It curves backwards to the posterior part of the side of the head It curves backwards to the posterior part of the side of the head superficial to the temporal fascia and ends by anastomosing with the occipital and superficial to the temporal fascia and ends by anastomosing with the occipital and posterior auricular arteries. posterior auricular arteries.

MAXILLARY ARTERY (INTERNAL MAXILLARY)MAXILLARY ARTERY (INTERNAL MAXILLARY) It is the larger terminal branch of the It is the larger terminal branch of the

external carotid artery and begins from external carotid artery and begins from opposite the neck of the mandible and opposite the neck of the mandible and the sphenomandibular ligament and the sphenomandibular ligament and crossing the inferior alveolar (dental) crossing the inferior alveolar (dental) nerve it reaches the lower border of nerve it reaches the lower border of the lateral pterygoid muscle. Then it the lateral pterygoid muscle. Then it ascends upwards crossing superficial ascends upwards crossing superficial to the lower head of the lateral to the lower head of the lateral pterygoid muscle and then it passes pterygoid muscle and then it passes medially between the two heads of the medially between the two heads of the lateral pterygoid muscle and enters the lateral pterygoid muscle and enters the pterygopalatine fossa through the pterygopalatine fossa through the pterygomaxillary fissure and ends pterygomaxillary fissure and ends dividing into its terminal branches. dividing into its terminal branches.

The portion of the maxillary The portion of the maxillary artery extending from its origin to the artery extending from its origin to the lower border of the lateral pterygoid lower border of the lateral pterygoid muscle constitutes its first part, the muscle constitutes its first part, the portion extending over the lateral portion extending over the lateral pterygoid muscle constitutes its pterygoid muscle constitutes its second or pterygoid part and the second or pterygoid part and the portion extending from between the portion extending from between the two heads of the lateral pterygoid two heads of the lateral pterygoid muscle to the pterygopalatine fossa muscle to the pterygopalatine fossa constitutes its third or the constitutes its third or the pterygopalatine part. pterygopalatine part.

MAXILLARY ARTERY (INTERNAL MAXILLARY)MAXILLARY ARTERY (INTERNAL MAXILLARY) Branches from the first part of the Branches from the first part of the

maxillary artery (five branches) :maxillary artery (five branches) : Deep auricular Deep auricular Anterior tympanic Anterior tympanic Middle meningeal Middle meningeal Accessory meningeal Accessory meningeal Inferior alveolar (dental) Inferior alveolar (dental) Branches from the second part (four Branches from the second part (four

branches) :branches) : Deep temporal Deep temporal Pterygoid Pterygoid Masseteric Masseteric Buccal Buccal Branches from the third part (six Branches from the third part (six

branches) :branches) : Posterior superior alveolar (dental) Posterior superior alveolar (dental) Infra – orbital Infra – orbital Greater palatine Greater palatine Pharyngeal Pharyngeal Artery of the pterygoid canal Artery of the pterygoid canal Sphenopalatine Sphenopalatine

MAXILLARY ARTERYMAXILLARY ARTERY The deep auricular artery is the first branch of the (internal) maxillary artery and ascends The deep auricular artery is the first branch of the (internal) maxillary artery and ascends

upwards behind the mandibular joint where it gives a twig to the same. Then it pierces the upwards behind the mandibular joint where it gives a twig to the same. Then it pierces the cartilage of the pina of the ear and ends by supplying the external surface of the tympanic cartilage of the pina of the ear and ends by supplying the external surface of the tympanic membrane.membrane.

The anterior tympanic artery is smaller than the preceding artery and ascends upwards behind The anterior tympanic artery is smaller than the preceding artery and ascends upwards behind the mandibular joint and then it enters the tympanic cavity through the pterygotympanic fissure. the mandibular joint and then it enters the tympanic cavity through the pterygotympanic fissure. In the tympanic cavity it ramifies on the internal surface of the tympanic membrane; by In the tympanic cavity it ramifies on the internal surface of the tympanic membrane; by anastomosing with the posterior tympanic branch of the stylomastoid artery it forms a vascular anastomosing with the posterior tympanic branch of the stylomastoid artery it forms a vascular ring around the tympanic membrane. It also anastomoses with the caroticotympanic and the ring around the tympanic membrane. It also anastomoses with the caroticotympanic and the artery of the pterygoid canal. artery of the pterygoid canal.

The middle meningeal artery is the largest of the meningeal arteries and arises from the first The middle meningeal artery is the largest of the meningeal arteries and arises from the first portion of the maxillary artery. portion of the maxillary artery.

At its origin it lies between the sphenomandibular ligament and the lateral pterygoid muscle. Then At its origin it lies between the sphenomandibular ligament and the lateral pterygoid muscle. Then as it ascends upwards behind the lateral pterygoid muscle it is encircled by the two roots of the as it ascends upwards behind the lateral pterygoid muscle it is encircled by the two roots of the auriculotemporal nerve and lies on the tensor palati muscle and is crossed by the chorda tympani auriculotemporal nerve and lies on the tensor palati muscle and is crossed by the chorda tympani nerve and then it enters the cranial cavity through the foramen spinosum accompanied by the nerve and then it enters the cranial cavity through the foramen spinosum accompanied by the meningeal branch of the mandibular nerve (nervous spinosus): then it leaves the nerve and runs meningeal branch of the mandibular nerve (nervous spinosus): then it leaves the nerve and runs forwards and laterally in a groove on the squamous part of the temporal bone and then divides forwards and laterally in a groove on the squamous part of the temporal bone and then divides into the anterior and posterior branches. into the anterior and posterior branches.

The anterior branch of the middle meningeal artery crosses the greater wing of the sphenoid The anterior branch of the middle meningeal artery crosses the greater wing of the sphenoid bone and then enters in a groove on the antero-inferior angle of the parietal bone; here it divides bone and then enters in a groove on the antero-inferior angle of the parietal bone; here it divides into branches which ascend upwards and backwards between the dura mater and the cranium to into branches which ascend upwards and backwards between the dura mater and the cranium to the summit of the cranial cavity where it ends by anastomosing with the similar branches from the the summit of the cranial cavity where it ends by anastomosing with the similar branches from the opposite side. One of its branches is large and ascends vertically upwards at a distance of about opposite side. One of its branches is large and ascends vertically upwards at a distance of about 1.5 cm from the coronal suture. 1.5 cm from the coronal suture.

The posterior branch of the middle meningeal artery runs upwards and backwards in the The posterior branch of the middle meningeal artery runs upwards and backwards in the posterior part of the squamous part of the temporal bone and reaches the parietal bone a little in posterior part of the squamous part of the temporal bone and reaches the parietal bone a little in front of its postero-inferior angle and finally divides into branches which supply the dura mater in front of its postero-inferior angle and finally divides into branches which supply the dura mater in the posterior part of the cranium and end by anastomosing with the branches from the opposite the posterior part of the cranium and end by anastomosing with the branches from the opposite side. side.

MAXILLARY ARTERYMAXILLARY ARTERY

Branches :Branches : Ganglionic. It supplies the trigeminal ganglion Ganglionic. It supplies the trigeminal ganglion Superficial petrosal. It enters the tympanic cavity through the hiatus Superficial petrosal. It enters the tympanic cavity through the hiatus

of the greater superficial petrosal nerve and supplies the tympanic of the greater superficial petrosal nerve and supplies the tympanic cavitycavity

Superior tympanic. It enters the tympanic cavity through the canal Superior tympanic. It enters the tympanic cavity through the canal for the tensor tympani muscle and supplies the tympanic cavity. for the tensor tympani muscle and supplies the tympanic cavity.

Temporal branches. They come out in the temporal fossa by Temporal branches. They come out in the temporal fossa by passing through minute foramina in the greater wing of the sphenoid passing through minute foramina in the greater wing of the sphenoid bone and ends by anastomosing with deep temporal arteries. bone and ends by anastomosing with deep temporal arteries.

Orbital. It enters the orbit through the superior orbital fissure and Orbital. It enters the orbit through the superior orbital fissure and ends by anastomosing with the recurrent meningeal branch of the ends by anastomosing with the recurrent meningeal branch of the lacrimal artery. lacrimal artery.

Terminal (anterior and posterior). Terminal (anterior and posterior).

The accessory meningeal artery arises either from the (internal) maxillary or from the The accessory meningeal artery arises either from the (internal) maxillary or from the middle meningeal artery and enters the cranial cavity through the foramen ovale. In middle meningeal artery and enters the cranial cavity through the foramen ovale. In the cranial cavity it supplies branches to the dura mater and the trigeminal ganglion. the cranial cavity it supplies branches to the dura mater and the trigeminal ganglion.

The inferior alveolar (dental) artery arises from the lower border of the first part of the The inferior alveolar (dental) artery arises from the lower border of the first part of the maxillary artery and descends on the medical aspect of the ramus of the mandible to maxillary artery and descends on the medical aspect of the ramus of the mandible to the mandibular foramen. It then enters the mandibular canal in company with the the mandibular foramen. It then enters the mandibular canal in company with the inferior alveolar (dental) nerve and reaching the level of the first premolar tooth it ends inferior alveolar (dental) nerve and reaching the level of the first premolar tooth it ends by dividing into incisive and mental branches. In its course to the mandibular foramen by dividing into incisive and mental branches. In its course to the mandibular foramen it intervenes between the ramus of the mandible and the sphenomandibular ligament it intervenes between the ramus of the mandible and the sphenomandibular ligament and lies posterior to the inferior alveolar (dental) nerve. Just before it enters into the and lies posterior to the inferior alveolar (dental) nerve. Just before it enters into the mandibular canal it gives out its lingual branch which accompanies the lingual nerve mandibular canal it gives out its lingual branch which accompanies the lingual nerve and supplies the tongue. and supplies the tongue.

The mylohyoid branch arises from the inferior alveolar (dental) artery and after piercing The mylohyoid branch arises from the inferior alveolar (dental) artery and after piercing the sphenomandibular ligament it descends on the mylohyoid groove together with the the sphenomandibular ligament it descends on the mylohyoid groove together with the mylohyoid nerve. It ramifies on the surface of the mylohyoid muscle and anastomoses mylohyoid nerve. It ramifies on the surface of the mylohyoid muscle and anastomoses with the submental branch of the facial artery. with the submental branch of the facial artery.

The incisive branch of the inferior alveolar artery reaches the median plane by passing The incisive branch of the inferior alveolar artery reaches the median plane by passing below the incisor teeth and ends by anastomosing with fellow of its opposite side. In its below the incisor teeth and ends by anastomosing with fellow of its opposite side. In its course it supplies the incisor teeth. course it supplies the incisor teeth.

The mental branch of the inferior alveolar artery comes out through the mental The mental branch of the inferior alveolar artery comes out through the mental foramen and supplies then chin. It anastomoses with the submental and inferior labial foramen and supplies then chin. It anastomoses with the submental and inferior labial branches of the facial artery. branches of the facial artery.

The deep temporal branches of the (internal) maxillary artery are anterior and posterior The deep temporal branches of the (internal) maxillary artery are anterior and posterior and they ascend to the temporal fossa between the temporalis muscle and the and they ascend to the temporal fossa between the temporalis muscle and the pericranium. They supply the temporalis muscle and anastomose with the middle pericranium. They supply the temporalis muscle and anastomose with the middle temporal artery. The anterior deep temporal artery gives a branch which pierces the temporal artery. The anterior deep temporal artery gives a branch which pierces the zygomatic bone and the greater wing of the sphenoid and anastomoses with the zygomatic bone and the greater wing of the sphenoid and anastomoses with the lacrimal artery. lacrimal artery.

The pterygoid branches of the (internal) maxillary artery supply the pterygoid muscles. The pterygoid branches of the (internal) maxillary artery supply the pterygoid muscles.

MAXILLARY ARTERYMAXILLARY ARTERY

The infraorbital artery usually in The infraorbital artery usually in common with the preceding artery and common with the preceding artery and enters the orbital cavity through the enters the orbital cavity through the posterior part of the inferior orbital posterior part of the inferior orbital fissure. It accompanies the infraorbital fissure. It accompanies the infraorbital nerve and runs in the infraorbital nerve and runs in the infraorbital groove or canal on the floor of the groove or canal on the floor of the orbit. It emerges to the face through orbit. It emerges to the face through the infraorbital foramen and lies under the infraorbital foramen and lies under the cover of the levator labii superioris. the cover of the levator labii superioris. In the face its terminal branches In the face its terminal branches anastomose with the branches of the anastomose with the branches of the facial, the transverse facial, the buccal facial, the transverse facial, the buccal arteries and the dorsal nasal branch of arteries and the dorsal nasal branch of the ophthalmic artery. In the orbit it the ophthalmic artery. In the orbit it gives out orbital branches which gives out orbital branches which supply some twigs to the rectus supply some twigs to the rectus inferior, the obliques inferior and the inferior, the obliques inferior and the lacrimal sac and by its anterior lacrimal sac and by its anterior superior alveolar (dental) arteries superior alveolar (dental) arteries supplies the maxillary air sinus, the supplies the maxillary air sinus, the incisors and the canine tooth. incisors and the canine tooth.

THE INTERNAL CAROTID ARTERY :THE INTERNAL CAROTID ARTERY :

The internal carotid artery begins The internal carotid artery begins at the bifurcation of the common at the bifurcation of the common carotid artery opposite the upper carotid artery opposite the upper border of the thyroid cartilage and border of the thyroid cartilage and ascending upwards through the ascending upwards through the neck it enters the carotid canal of neck it enters the carotid canal of the petrous part of the temporal the petrous part of the temporal bone and emerges from the latter bone and emerges from the latter into the cranial cavity where it is at into the cranial cavity where it is at first contained within the first contained within the cavernous sinus and then cavernous sinus and then emerges out of it to reach the emerges out of it to reach the base of the brain where it divides base of the brain where it divides into the branches which are into the branches which are distributed to the brain. Thus the distributed to the brain. Thus the internal carotid artery may be internal carotid artery may be divided into cervical, petrous divided into cervical, petrous cavernous and cerebral parts. cavernous and cerebral parts.

THE INTERNAL CAROTID ARTERYTHE INTERNAL CAROTID ARTERY

Cervical part of the internal carotid artery :Cervical part of the internal carotid artery : The internal carotid artery in the neck The internal carotid artery in the neck is contained within the upward prolongation of the carotid sheath along with the is contained within the upward prolongation of the carotid sheath along with the internal jugular vein and the vagus nerve. Posteriorly, it lies mostly on the longus internal jugular vein and the vagus nerve. Posteriorly, it lies mostly on the longus capitis muscle being separated by the prevertebral fascia, the superior laryngeal capitis muscle being separated by the prevertebral fascia, the superior laryngeal nerve, the superior cervical sympathetic ganglion and the carotid sheath. Anteriorly, nerve, the superior cervical sympathetic ganglion and the carotid sheath. Anteriorly, below the posterior belly of the digastric it is overlapped by the sternomastoid muscle below the posterior belly of the digastric it is overlapped by the sternomastoid muscle and is crossed by the sternomastoid muscle and is crossed by the hypoglossal nerve, and is crossed by the sternomastoid muscle and is crossed by the hypoglossal nerve, the (common) facial vein and the occipital artery being separated by the carotid the (common) facial vein and the occipital artery being separated by the carotid sheath. Above it passes deep to the posterior belly of the digastric,s tylohyoid, styloid sheath. Above it passes deep to the posterior belly of the digastric,s tylohyoid, styloid process and the other styloid group of muscles. The styloid process with the styloid process and the other styloid group of muscles. The styloid process with the styloid group of muscles separates it from the parotid group of muscles separates it from the group of muscles separates it from the parotid group of muscles separates it from the parotid gland, the external carotid artery, the retromandibular (posterior facial) vein parotid gland, the external carotid artery, the retromandibular (posterior facial) vein and the facial nerve. Beneath the stylopharyngeus muscle it is crossed by the and the facial nerve. Beneath the stylopharyngeus muscle it is crossed by the glossopharyngeus muscle it is crossed by the glossopharyngeal nerve and the glossopharyngeus muscle it is crossed by the glossopharyngeal nerve and the pharyngeal branch of the vagus nerve. Laterally, it is related to the internal jugular pharyngeal branch of the vagus nerve. Laterally, it is related to the internal jugular vein and the vagus nerve. Just before it enters into the carotid canal of the petrous vein and the vagus nerve. Just before it enters into the carotid canal of the petrous part of the temporal bone, the glossopharyngeal, vagus, the accessory and part of the temporal bone, the glossopharyngeal, vagus, the accessory and hypoglossal nerves and the internal jugular vein lays anterolateral to it. The cervical hypoglossal nerves and the internal jugular vein lays anterolateral to it. The cervical part of the internal carotid artery does not provide any branches. part of the internal carotid artery does not provide any branches.

Petrous part of the internal carotid artery : The internal carotid artery Petrous part of the internal carotid artery : The internal carotid artery traverses through the carotid canal in the petrous part of the temporal bone and then traverses through the carotid canal in the petrous part of the temporal bone and then enters the cavernous part. enters the cavernous part.

THE INTERNAL CAROTID ARTERYTHE INTERNAL CAROTID ARTERY Cavernous and cerebral parts of the internal carotid artery :Cavernous and cerebral parts of the internal carotid artery : The cavernous part The cavernous part

of the internal carotid artery lies within the cavernous sinus and is separated from the of the internal carotid artery lies within the cavernous sinus and is separated from the blood of the sinus by the lining endothelium of the same. inferolateral to it is the blood of the sinus by the lining endothelium of the same. inferolateral to it is the abducent, nerve and more laterally are the oculomotor, trochlear, ophthalmic and abducent, nerve and more laterally are the oculomotor, trochlear, ophthalmic and maxillary nerves. It perforates the dura mater forming the roof of the sinus medial to maxillary nerves. It perforates the dura mater forming the roof of the sinus medial to the anterior clinoid process. Then it runs backwards below the optic nerve and runs the anterior clinoid process. Then it runs backwards below the optic nerve and runs between the optic and oculomotor nerves to the anterior perforated substance and between the optic and oculomotor nerves to the anterior perforated substance and lies on the medial side of the lateral anterior and middle cerebral arteries. lies on the medial side of the lateral anterior and middle cerebral arteries.

Branches :Branches : Cavernous part :Cavernous part : Cavernous Cavernous Hypophyseal Hypophyseal Meningeal Meningeal Ophthalmic Ophthalmic Petrous part :Petrous part : Caroticotympanic Caroticotympanic Pterygoid Pterygoid Cerebral part :Cerebral part : Anterior cerebral Anterior cerebral Middle cerebral Middle cerebral Posterior communicating Posterior communicating Anterior choroid.Anterior choroid.

THE INTERNAL CAROTID ARTERYTHE INTERNAL CAROTID ARTERY

The ophthalmic artery arises from the internal The ophthalmic artery arises from the internal carotid artery opposite the level of the optic carotid artery opposite the level of the optic foramen and passes through the same lying foramen and passes through the same lying inferolateral to the optic nerve and enters the inferolateral to the optic nerve and enters the orbital cavity and then soon crosses the optic orbital cavity and then soon crosses the optic nerve from the lateral to the medial side to reach nerve from the lateral to the medial side to reach the medial wall of the orbit. Then it passes to the the medial wall of the orbit. Then it passes to the medial margin of the front of the orbit where it medial margin of the front of the orbit where it breaks up into its terminal branches, frontal and breaks up into its terminal branches, frontal and dorsal nasal. The following are the branches of dorsal nasal. The following are the branches of the ophthalmic artery: the ophthalmic artery:

Branches :Branches : Lacrimal artery :Lacrimal artery : It accompanies the lacrimal It accompanies the lacrimal

nerve and supplies the lacrimal gland and the nerve and supplies the lacrimal gland and the conjunctiva and the eyelids. Opposite the lateral conjunctiva and the eyelids. Opposite the lateral palpebral commissure it divides into two lateral palpebral commissure it divides into two lateral palpebral arteries which anastomose with the palpebral arteries which anastomose with the medial palpebral arteries to form the arcus medial palpebral arteries to form the arcus tarseus. It also gives out zygomatic and tarseus. It also gives out zygomatic and recurrent meningeal braches. The zygomatic recurrent meningeal braches. The zygomatic branches are usually two in number, one passes branches are usually two in number, one passes to the temporal fossa by passing through the to the temporal fossa by passing through the zygomaticotemporal foramen and ends by zygomaticotemporal foramen and ends by anatomosing with the deep temporal arteries; anatomosing with the deep temporal arteries; the other branch passes to the face through the the other branch passes to the face through the zygomaticofacial foramen and ends by zygomaticofacial foramen and ends by anastomosing with the transverse facial branch anastomosing with the transverse facial branch of the superficial temporal artery. The recurrent of the superficial temporal artery. The recurrent meningeal branch of the lacrimal artery runs meningeal branch of the lacrimal artery runs backwards and enters the cranial cavity through backwards and enters the cranial cavity through the lateral part of the superior orbital fissure, the lateral part of the superior orbital fissure, lying outside the annulus tendineus communis lying outside the annulus tendineus communis and ends by anastomosing with a branch of the and ends by anastomosing with a branch of the middle meningeal atery. middle meningeal atery.

THE SUBCLAVIAN ARTERIES :THE SUBCLAVIAN ARTERIES : The left subclavian artery arises The left subclavian artery arises

from the arch of the aorta and from the arch of the aorta and after a short course in the thorax it after a short course in the thorax it enters the neck. The right enters the neck. The right suclavian artery arises from the suclavian artery arises from the brachiocephalic (innominate) brachiocephalic (innominate) artery. In the neck the scalenus artery. In the neck the scalenus anterior muscle crosses in front of anterior muscle crosses in front of the artery and subdivides it into the artery and subdivides it into three parts – first, second and three parts – first, second and third. The first part extends from third. The first part extends from its origin to the medial border of its origin to the medial border of the scalenus anterior, the second the scalenus anterior, the second part lies under the cover of the part lies under the cover of the scalenus anterior while the third scalenus anterior while the third part extends from the lateral part extends from the lateral border of the scalenus anterior or border of the scalenus anterior or the outer border of the first rib the outer border of the first rib where it is continued as the where it is continued as the axillary artery. The first portion of axillary artery. The first portion of the left subclavian artery is longer the left subclavian artery is longer than the right. than the right.

THE SUBCLAVIAN ARTERIES :THE SUBCLAVIAN ARTERIES :

First portion of the subclavian artery enters the neck behind the upper part First portion of the subclavian artery enters the neck behind the upper part of the sternoclavicular articulation and arches upwards and laterally to reach of the sternoclavicular articulation and arches upwards and laterally to reach the medial margin of the scalenus anterior where it becomes continuous the medial margin of the scalenus anterior where it becomes continuous with the second part. Anteriorly, it is covered by the skin, superficial fascia, with the second part. Anteriorly, it is covered by the skin, superficial fascia, platysma, deep fascia, clavicular origin of the sternomastoid and the origins platysma, deep fascia, clavicular origin of the sternomastoid and the origins of the sternohyoid and sternothyroid muscles. It is crossed in front by the of the sternohyoid and sternothyroid muscles. It is crossed in front by the internal jugular vein, vagus and cardiac nerves and the vertebral veins. internal jugular vein, vagus and cardiac nerves and the vertebral veins. Close to the scalenus anterior it is encircled by the ansa subclavia from the Close to the scalenus anterior it is encircled by the ansa subclavia from the sympathetic nerve and on the left phrenic nerve and the thoracic duct. sympathetic nerve and on the left phrenic nerve and the thoracic duct. Postero-inferiorly, it is related to the apex of the lung but is separated from it Postero-inferiorly, it is related to the apex of the lung but is separated from it by the pleura and the supraleural membrane, the recurrent laryngeal nerve by the pleura and the supraleural membrane, the recurrent laryngeal nerve and the ansa subclavia. The recurrent laryngeal nerve comes into relation and the ansa subclavia. The recurrent laryngeal nerve comes into relation with the subclavain artery on the right side only and after its origin from the with the subclavain artery on the right side only and after its origin from the right vagus nerve as it crosses in front of the artery it hooks round below it. right vagus nerve as it crosses in front of the artery it hooks round below it. Posteriorly, it is related to the sympathetic trunk, the longus cervicis muscle, Posteriorly, it is related to the sympathetic trunk, the longus cervicis muscle, the right recurrent laryngeal nerve and the first thoracic vertebra. the right recurrent laryngeal nerve and the first thoracic vertebra.

Second portion of the subclavian artery :Second portion of the subclavian artery :

THE SUBCLAVIAN ARTERIES :THE SUBCLAVIAN ARTERIES :

Second portion of the subclavian artery :Second portion of the subclavian artery : The second portion of The second portion of the subcalvain artery lies behind the scalenus anterior and forms an the subcalvain artery lies behind the scalenus anterior and forms an arch, the summit of which is about 2.0 cm above the clavicle. arch, the summit of which is about 2.0 cm above the clavicle. Anteriorly, it is covered by the skin, superficial fascia, platysma, Anteriorly, it is covered by the skin, superficial fascia, platysma, deep fascia, sternomastoid and scalenus anterior muscles. On the deep fascia, sternomastoid and scalenus anterior muscles. On the right side, the pherenic nerve crosses in front of it being separated right side, the pherenic nerve crosses in front of it being separated by the scalenus anterior. Postero-inferiorly, it is related to the lung by the scalenus anterior. Postero-inferiorly, it is related to the lung and pleura. Antero-inferiorly, it is related to the subclavian vein and pleura. Antero-inferiorly, it is related to the subclavian vein being separated by the scalenus anterior. Superiorly, it comes into being separated by the scalenus anterior. Superiorly, it comes into relation with the upper and the middle trunks of the brachial plexus. relation with the upper and the middle trunks of the brachial plexus.

Branches : From the first part :Branches : From the first part : Vertebral Vertebral Thyrocervical trunk Thyrocervical trunk Internal thoracic (mammary) Internal thoracic (mammary) Costocervical trunk (left side) Costocervical trunk (left side) From the second part (right side) : costocervical trunk. From the second part (right side) : costocervical trunk.

Vertebral arteryVertebral artery The vertebral artery arises from the posterosuperior part The vertebral artery arises from the posterosuperior part

of the first portion of the subclavian artery and ascends of the first portion of the subclavian artery and ascends upwards to reach the foramen transversarium of the upwards to reach the foramen transversarium of the sixth cervical vertebra and then passes upwards through sixth cervical vertebra and then passes upwards through the foramina in the transverse processes of the cervical the foramina in the transverse processes of the cervical vertebrae and then winds backwards behind the lateral vertebrae and then winds backwards behind the lateral mass of the atlas and reaches the groove on the upper mass of the atlas and reaches the groove on the upper surface of the posterior arch of the atlas. Finally, it enters surface of the posterior arch of the atlas. Finally, it enters the cranium through the foramen magnum and reaching the cranium through the foramen magnum and reaching the lower part of the pons it unites with the fellow of its the lower part of the pons it unites with the fellow of its opposite side from the basilar artery. It is divisible into opposite side from the basilar artery. It is divisible into four parts. The first part begins from its origin to the four parts. The first part begins from its origin to the foramen transversarium of the sixth cervical vertebra, the foramen transversarium of the sixth cervical vertebra, the second part extends from the latter to the foramen second part extends from the latter to the foramen transversarium of the atlas, the third part of contained in transversarium of the atlas, the third part of contained in the suboccipital triangle while the fourth part is the suboccipital triangle while the fourth part is contained within the cranial cavity. contained within the cranial cavity.

Vertebral arteryVertebral artery

BRANCHES :BRANCHES :1.1. Cervical part : Cervical part : 2.2. Muscular branchesMuscular branches3.3. Spinal branchesSpinal branches4.4. Meningeal branches Meningeal branches 5.5. Cranial part :Cranial part :6.6. Posterior spinal artery Posterior spinal artery 7.7. Anterior spinal artery Anterior spinal artery 8.8. Posterior inferior cerebellar artery. Posterior inferior cerebellar artery.

CAROTID ARTERY LIGATION :CAROTID ARTERY LIGATION : The management of the compromised carotid artery is The management of the compromised carotid artery is

one of the most difficult problems in head and neck one of the most difficult problems in head and neck surgery. The internal and common carotid arteries, surgery. The internal and common carotid arteries, however, can be electively ligated only after careful however, can be electively ligated only after careful evaluation of the adequacy of the collateral cerebral evaluation of the adequacy of the collateral cerebral circulation, in order to avoid cerebral hypoperfusion and circulation, in order to avoid cerebral hypoperfusion and stroke. On the other hand, efforts to avoid ligation of the stroke. On the other hand, efforts to avoid ligation of the artery can predispose the patient to spontaneous rupture artery can predispose the patient to spontaneous rupture of the artery, requiring emergency resuscitation and of the artery, requiring emergency resuscitation and carotid ligation. carotid ligation.

Carotid ligation may be necessary for a variety of Carotid ligation may be necessary for a variety of reasons. It can be electively performed in patients with reasons. It can be electively performed in patients with cancer involving the carotid artery. More urgent ligation cancer involving the carotid artery. More urgent ligation may be indicated in patients with postoperative fistulas may be indicated in patients with postoperative fistulas or open wounds, often previously irradiated, who are at or open wounds, often previously irradiated, who are at high risk for spontaneous rupture of an exposed carotid. high risk for spontaneous rupture of an exposed carotid.

ELECTIVE CAROTID RESECTION FOR TUMORELECTIVE CAROTID RESECTION FOR TUMOR The goal in evaluating such a patient is to determine whether the The goal in evaluating such a patient is to determine whether the

collateral flow through the circle of Willis will sufficiently perfuse the brain. Most surgeons collateral flow through the circle of Willis will sufficiently perfuse the brain. Most surgeons advocate four-vessel cerebral arteriography as the first diagnostic test prior to carotid ligation. advocate four-vessel cerebral arteriography as the first diagnostic test prior to carotid ligation. This will evaluate the patency and displacement of all the vessels contributing to the circle of This will evaluate the patency and displacement of all the vessels contributing to the circle of Willis. In some situations, less invasive techniques such as compute tomography (CT) with digital Willis. In some situations, less invasive techniques such as compute tomography (CT) with digital subtraction and magnetic resonance (MR) angiography may be sufficient. Certainly in patients subtraction and magnetic resonance (MR) angiography may be sufficient. Certainly in patients with advanced tumors, CT or MR imaging will provide additional information regarding the with advanced tumors, CT or MR imaging will provide additional information regarding the relationship of the tumor to the carotid artery. relationship of the tumor to the carotid artery.

Though simple angiography may indicate an anatomically adequate collateral Though simple angiography may indicate an anatomically adequate collateral circulation, it does not necessarily predict which patients will tolerate carotid ligation. A variety of circulation, it does not necessarily predict which patients will tolerate carotid ligation. A variety of tests have been devised to provide such a prediction, both intraoperatively and preoperatively, tests have been devised to provide such a prediction, both intraoperatively and preoperatively, with varying success.with varying success.

For the intraoperative evaluation of candidates for carotid ligation, the measurement For the intraoperative evaluation of candidates for carotid ligation, the measurement of distal internal carotid stump pressures is the best technique. Ehrenfeld and colleagues showed of distal internal carotid stump pressures is the best technique. Ehrenfeld and colleagues showed that intraoperatively measured carotid stump pressures greater than 70 mm Hg predicted the that intraoperatively measured carotid stump pressures greater than 70 mm Hg predicted the safety of carotid ligation. Enzmann and associates subsequently developed a method for safety of carotid ligation. Enzmann and associates subsequently developed a method for measuring carotid back pressure angiographically. However, Steed and colleagues, in a larger measuring carotid back pressure angiographically. However, Steed and colleagues, in a larger series, showed that while there is a correlation between cerebral blood flow and carotid stump series, showed that while there is a correlation between cerebral blood flow and carotid stump pressures, the correlation is not exact. pressures, the correlation is not exact.

One of the earliest methods for the preoperative estimation of the ability to tolerate One of the earliest methods for the preoperative estimation of the ability to tolerate internal carotid occlusion was oculoplethysmography. This technique involves the assessment of internal carotid occlusion was oculoplethysmography. This technique involves the assessment of ophthalmic artery pressure by pressure measurements on the cornea. They found a good ophthalmic artery pressure by pressure measurements on the cornea. They found a good correlation with intraoperative carotid stump pressures. correlation with intraoperative carotid stump pressures.

More recent tests have been based on a preoperative trial of internal carotid artery More recent tests have been based on a preoperative trial of internal carotid artery occlusion in the awake patient. This has been performed both angiographically and surgically occlusion in the awake patient. This has been performed both angiographically and surgically under local anesthesia. During the trial occlusion, the patient can be evaluated through a variety under local anesthesia. During the trial occlusion, the patient can be evaluated through a variety of methods. One of the simplest is to observe for neurologic signs and symptoms. This of methods. One of the simplest is to observe for neurologic signs and symptoms. This reasonably assesses a patient’s ability to withstand temporary carotid occlusion. reasonably assesses a patient’s ability to withstand temporary carotid occlusion.

Carotid ligation – operative and perioperative Carotid ligation – operative and perioperative

managementmanagement : : When resecting a tumor involving the carotid artery, the extent of the When resecting a tumor involving the carotid artery, the extent of the

resection is dictated by the extent of disease. Whenever possible the resection is dictated by the extent of disease. Whenever possible the resection should be performed above the carotid bifurcation, thereby resection should be performed above the carotid bifurcation, thereby preserving the external carotid system with its potential collaterals to he preserving the external carotid system with its potential collaterals to he cerebral circulation. cerebral circulation.

Konno and colleagues discussed gradual carotid occlusion over Konno and colleagues discussed gradual carotid occlusion over several days; they believed that neurologic complications were decreased if several days; they believed that neurologic complications were decreased if the carotid occlusion was performed gradually over greater than 13 days. the carotid occlusion was performed gradually over greater than 13 days.

Surgical techniques for carotid ligation vary. In general, the artery Surgical techniques for carotid ligation vary. In general, the artery should be doubly ligation with a secure, permanent suture such as 0 or 00 should be doubly ligation with a secure, permanent suture such as 0 or 00 silk, and the end of the artery should be oversewn with a fine monofilament, silk, and the end of the artery should be oversewn with a fine monofilament, nonreactive vascular suture. During the ligation the anesthetic should seek nonreactive vascular suture. During the ligation the anesthetic should seek to maintain a higher blood pressure and to avoid blood pressure swings. to maintain a higher blood pressure and to avoid blood pressure swings.

The role of anticoagulation perioperatively in these cases is The role of anticoagulation perioperatively in these cases is unclear. It is common practice to give a single dose of 5000 units of heparin unclear. It is common practice to give a single dose of 5000 units of heparin intravenously when opening the carotid artery. Most surgeons are opposed intravenously when opening the carotid artery. Most surgeons are opposed to full anticoagulation is a patient who has undergone a major resection, and to full anticoagulation is a patient who has undergone a major resection, and in general stump thrombus has not represented a major problem. We in general stump thrombus has not represented a major problem. We routinely provide anticoagulation with heparin just before carotid clamping routinely provide anticoagulation with heparin just before carotid clamping and partially reverse it with protamine sulfate if oozing continues during and partially reverse it with protamine sulfate if oozing continues during closure of the skin flaps closure of the skin flaps

Alternatives to carotid ligationAlternatives to carotid ligation : : Despite advance in preoperative patient evaluation, cerebrovascular Despite advance in preoperative patient evaluation, cerebrovascular

accidents are always a risk in resection of the carotid artery. Postoperative accidents are always a risk in resection of the carotid artery. Postoperative carotid rupture is also a concern. Therefore, alternative ways of managing carotid rupture is also a concern. Therefore, alternative ways of managing these cases have been sought. If the patient with a fixed neck mass has not these cases have been sought. If the patient with a fixed neck mass has not received irradiation, many would support primary irradiation to be followed received irradiation, many would support primary irradiation to be followed by neck dissection, in the hope that this would allow removal of the tumor by neck dissection, in the hope that this would allow removal of the tumor from the artery without compromising the resection margins. from the artery without compromising the resection margins.

A surgical option supported by some is the so-called palliative peel, A surgical option supported by some is the so-called palliative peel, in the tumor is dissected off the artery in a subadventitial plane. However, in the tumor is dissected off the artery in a subadventitial plane. However, peeling through an artificial plane and leaving a vessel wall with a highly peeling through an artificial plane and leaving a vessel wall with a highly abnormal appearance probably represents an incomplete tumor resection. abnormal appearance probably represents an incomplete tumor resection. To prevent tumor recurrence, postoperative radiation may be used if this is To prevent tumor recurrence, postoperative radiation may be used if this is still an option. still an option.

Martinez and associates dealt with this problem by placing Martinez and associates dealt with this problem by placing radioactive iodine seeds on the involved areas of the carotid after peeling radioactive iodine seeds on the involved areas of the carotid after peeling the mass off the artery. the mass off the artery.

A second alternative to carotid ligation is carotid resection followed A second alternative to carotid ligation is carotid resection followed by reconstruction of the artery. It has been clearly shown that this can be by reconstruction of the artery. It has been clearly shown that this can be performed safely in noninfected and nonirradiated fields. The major advance performed safely in noninfected and nonirradiated fields. The major advance has been the use of myocutaneous flaps to cover the reconstructed artery. has been the use of myocutaneous flaps to cover the reconstructed artery. In addition, most surgeons prefer the use of saphenous vein interposition In addition, most surgeons prefer the use of saphenous vein interposition grafts rather that prosthetic materials, after several complications were grafts rather that prosthetic materials, after several complications were noted with the use of Gore-tex grafts noted with the use of Gore-tex grafts

PREVENTION OF CAROTID RUPTUREPREVENTION OF CAROTID RUPTURE Despite advance in preoperative patient evaluation, cerebrovascular Despite advance in preoperative patient evaluation, cerebrovascular

accidents are always a risk in resection of the carotid artery. accidents are always a risk in resection of the carotid artery. Postoperative carotid rupture is also a concern. Therefore, Postoperative carotid rupture is also a concern. Therefore, alternative ways of managing these cases have been sought. If the alternative ways of managing these cases have been sought. If the patient with a fixed neck mass has not received irradiation, many patient with a fixed neck mass has not received irradiation, many would support primary irradiation to be followed by neck dissection, would support primary irradiation to be followed by neck dissection, in the hope that this would allow removal of the tumor from the in the hope that this would allow removal of the tumor from the artery without compromising the resection margins. artery without compromising the resection margins.

A surgical option supported by some is the so-called A surgical option supported by some is the so-called palliative peel, in the tumor is dissected off the artery in a palliative peel, in the tumor is dissected off the artery in a subadventitial plane. However, peeling through an artificial plane subadventitial plane. However, peeling through an artificial plane and leaving a vessel wall with a highly abnormal appearance and leaving a vessel wall with a highly abnormal appearance probably represents an incomplete tumor resection. To prevent probably represents an incomplete tumor resection. To prevent tumor recurrence, postoperative radiation may be used if this is still tumor recurrence, postoperative radiation may be used if this is still an option. an option.

Martinez and associates dealt with this problem by placing Martinez and associates dealt with this problem by placing radioactive iodine seeds on the involved areas of the carotid after radioactive iodine seeds on the involved areas of the carotid after peeling the mass off the artery. peeling the mass off the artery.

PREVENTION OF CAROTID RUPTUREPREVENTION OF CAROTID RUPTURE

A second alternative to carotid ligation is carotid A second alternative to carotid ligation is carotid resection followed by reconstruction of the resection followed by reconstruction of the artery. It has been clearly shown that this can be artery. It has been clearly shown that this can be performed safely in noninfected and performed safely in noninfected and nonirradiated fields. The major advance has nonirradiated fields. The major advance has been the use of myocutaneous flaps to cover the been the use of myocutaneous flaps to cover the reconstructed artery. In addition, most surgeons reconstructed artery. In addition, most surgeons prefer the use of saphenous vein interposition prefer the use of saphenous vein interposition grafts rather that prosthetic materials, after grafts rather that prosthetic materials, after several complications were noted with the use of several complications were noted with the use of Gore-tex grafts. Gore-tex grafts.

MANAGEMENT OF SPONTANEOUS CAROTID ARTERY RUPTUREMANAGEMENT OF SPONTANEOUS CAROTID ARTERY RUPTURE :: arotid artery rupture occurs in 3 per cent to 12 per cent of patients who Chave been treated with arotid artery rupture occurs in 3 per cent to 12 per cent of patients who Chave been treated with

radiation and surgery. Because of its infrequency, appropriate management may be delayed by radiation and surgery. Because of its infrequency, appropriate management may be delayed by physicians and nurses unaccustomed to this problem. physicians and nurses unaccustomed to this problem.

Several measures can increase success in salvaging patients after carotid rupture. Several measures can increase success in salvaging patients after carotid rupture. Multiple units for blood should be readily available for any patient who is at risk. When rupture Multiple units for blood should be readily available for any patient who is at risk. When rupture occurs, the patient should be packed immediately, and pressure should be held as needed to occurs, the patient should be packed immediately, and pressure should be held as needed to control bleeding as much as possible. Attempts at vessel ligation, however, should be deferred control bleeding as much as possible. Attempts at vessel ligation, however, should be deferred unless the vessel is immediately visible in an open wound and easily clamped. Otherwise, fluid unless the vessel is immediately visible in an open wound and easily clamped. Otherwise, fluid resuscitation and replacement of blood volume should precede attempts to control hemorrhage, resuscitation and replacement of blood volume should precede attempts to control hemorrhage, to minimize neurologic damage and decrease intraoperative mortality. A central catheter should to minimize neurologic damage and decrease intraoperative mortality. A central catheter should be placed early to assist in assessment of appropriate fluid resuscitation. Four large-bore be placed early to assist in assessment of appropriate fluid resuscitation. Four large-bore peripheral intravenous lines also should be inserted. Crystalloid and blood should be infused until peripheral intravenous lines also should be inserted. Crystalloid and blood should be infused until the systolic blood pressure is stabilized at greater then 110 mm Hg. The airway must be the systolic blood pressure is stabilized at greater then 110 mm Hg. The airway must be controlled immediately and a PO2 greater than 70 mm Hg must be maintained with ventilation if controlled immediately and a PO2 greater than 70 mm Hg must be maintained with ventilation if necessary. An operative procedure is delayed until these steps are taken. necessary. An operative procedure is delayed until these steps are taken.

When the patient has been appropriately prepared, he or she may be taken to When the patient has been appropriately prepared, he or she may be taken to surgery. The operation may be performed under local anesthesia if the risk of general anesthesia surgery. The operation may be performed under local anesthesia if the risk of general anesthesia is too high. The procedure is performed in a manner similar to that described for planned is too high. The procedure is performed in a manner similar to that described for planned preventive ligation. Porto and associates emphasized the importance of ligating the carotid artery preventive ligation. Porto and associates emphasized the importance of ligating the carotid artery proximally and distally through separate incisions, to avoid placing the stump in an infected field. proximally and distally through separate incisions, to avoid placing the stump in an infected field. To achieve this, they state that one incision must occasionally be placed below the clavicle and To achieve this, they state that one incision must occasionally be placed below the clavicle and the clavicle resected. the clavicle resected.

Postoperatively, the patients require placement in an acute care setting. They are Postoperatively, the patients require placement in an acute care setting. They are often elderly and may be debilitated by cancer. Underlying pulmonary disease is often present. often elderly and may be debilitated by cancer. Underlying pulmonary disease is often present. They have received large amounts of fluids and blood products and are at risk for stroke. Swan-They have received large amounts of fluids and blood products and are at risk for stroke. Swan-Ganz catheter placement is commonly needed to manage fluids appropriately. Prolonged Ganz catheter placement is commonly needed to manage fluids appropriately. Prolonged ventilator support also may prove necessary. Blood pressure should be maintained in the high-ventilator support also may prove necessary. Blood pressure should be maintained in the high-normal range to maximize cerebral effusion. A patient who survives may remain in guarded normal range to maximize cerebral effusion. A patient who survives may remain in guarded condition for several days after the event.condition for several days after the event.

NECK INCISIONS AND CAROTID RUPTURENECK INCISIONS AND CAROTID RUPTURE The carotid artery is at greatest risk for exposure and subsequent rupture The carotid artery is at greatest risk for exposure and subsequent rupture

when radical neck dissection is combined with resection of a primary lesion when radical neck dissection is combined with resection of a primary lesion involving any portion of the tongue, pharynx, and cervical esophagus. This involving any portion of the tongue, pharynx, and cervical esophagus. This is especially true following previous radiotherapy. Rupture of the carotid is especially true following previous radiotherapy. Rupture of the carotid artery is rare otherwise but can occur following any type of cervical skin artery is rare otherwise but can occur following any type of cervical skin necrosis and wound breakdown over the major vessels. Carotid artery necrosis and wound breakdown over the major vessels. Carotid artery blowout occurs most commonly at the bifurcation but may occur any-where blowout occurs most commonly at the bifurcation but may occur any-where along the course of the common or the internal carotid arteries. along the course of the common or the internal carotid arteries. Preoperative radiotherapy plays a major role in fistula formation and Preoperative radiotherapy plays a major role in fistula formation and infection. Radiation therapy causes endarteritis and fibrosis of the skin and infection. Radiation therapy causes endarteritis and fibrosis of the skin and underlying tissue, which decreases perfusion in virtually all areas. underlying tissue, which decreases perfusion in virtually all areas.

Skin incisions that are parallel to or lie directly over the carotid Skin incisions that are parallel to or lie directly over the carotid vessels are likely to expose these vessels when the skin edge sloughs. vessels are likely to expose these vessels when the skin edge sloughs. Carotid blowout is unavoidable when salivary contamination and infection Carotid blowout is unavoidable when salivary contamination and infection accompany skin slough. accompany skin slough.

Another cause for carotid artery blowout when associated with a Another cause for carotid artery blowout when associated with a fistula or infection, is direct injury to the blood vessel wall from suction fistula or infection, is direct injury to the blood vessel wall from suction catheters, tracheostomy tubes, or other prosthetic devices. Large vessel catheters, tracheostomy tubes, or other prosthetic devices. Large vessel blowout may occur without skin slough under an intact skin flap. This may blowout may occur without skin slough under an intact skin flap. This may happen when the skin is not in direct contact with blood vessels and is happen when the skin is not in direct contact with blood vessels and is associated with dead space and infection postoperative fistula associated associated with dead space and infection postoperative fistula associated with the contamination of the vessel wall and devitalisation of the vessel with the contamination of the vessel wall and devitalisation of the vessel adventita. adventita.

PREVENTION OF CAROTID ARTERY BLOWOUTPREVENTION OF CAROTID ARTERY BLOWOUT Patients with poor oral hygiene may benefit from an antibacterial mouthwash using 1 per cent Patients with poor oral hygiene may benefit from an antibacterial mouthwash using 1 per cent

clindamycin or 1 per cent neomycin 48 hours prior to the procedure. Preoperative antibiotics may clindamycin or 1 per cent neomycin 48 hours prior to the procedure. Preoperative antibiotics may be necessary. be necessary.

Skin incisions in the neck should be placed away from the great vessels and never Skin incisions in the neck should be placed away from the great vessels and never cross them. Some surgeons popularized the use of horizontal incisions (MacFee) as the solution cross them. Some surgeons popularized the use of horizontal incisions (MacFee) as the solution to this problem. However, skin slough may occur directly over the great vessels due to injury from to this problem. However, skin slough may occur directly over the great vessels due to injury from excessive retraction of the skin flaps during operation to obtain adequate exposure. Other types excessive retraction of the skin flaps during operation to obtain adequate exposure. Other types of skin flaps that avoid linear incisions over the vessels may include an inverted-Y incision or of skin flaps that avoid linear incisions over the vessels may include an inverted-Y incision or modifications of the apron flap. modifications of the apron flap.

Subplatysmal dissection of the skin flap should be done with great care to avoid Subplatysmal dissection of the skin flap should be done with great care to avoid damage to the blood supply. One must always include the cervical platysma in the flap unless damage to the blood supply. One must always include the cervical platysma in the flap unless there is a question of involvement of the platysma or skin by the neoplasm. In this situation, full there is a question of involvement of the platysma or skin by the neoplasm. In this situation, full thickness excision is essential to provide adequate oncologic margins. One must avoid possible thickness excision is essential to provide adequate oncologic margins. One must avoid possible trauma to the skin flap from clamps resting on and lying over the flaps during the operative trauma to the skin flap from clamps resting on and lying over the flaps during the operative procedure. Flaps must be protected with warm irrigation and moist laparotomy pads during the procedure. Flaps must be protected with warm irrigation and moist laparotomy pads during the entire procedure. One must also trim the edges of the flap at least 1 cm when viability is entire procedure. One must also trim the edges of the flap at least 1 cm when viability is questionable. questionable.

Special precautions should be taken to preserve skin perfusion in the case of prior Special precautions should be taken to preserve skin perfusion in the case of prior chemotherapy or radiation therapy. Suction drains are preferred to decrease dead space and chemotherapy or radiation therapy. Suction drains are preferred to decrease dead space and allow proper opposition of the skin flaps. Drains should not cross the base of the skin flap, which allow proper opposition of the skin flaps. Drains should not cross the base of the skin flap, which could compromise perfusion. Drains should be secured with absorbable sutures and placement could compromise perfusion. Drains should be secured with absorbable sutures and placement confirmed with neck mobility. When electrodissection is used to raise skin flaps, excessive heat confirmed with neck mobility. When electrodissection is used to raise skin flaps, excessive heat must be avoided. The lowest possible current setting should be used to prevent thermal injury. must be avoided. The lowest possible current setting should be used to prevent thermal injury. Extreme care must be given to creating a watertight closure of defects in the upper aerodigestive Extreme care must be given to creating a watertight closure of defects in the upper aerodigestive tract (e.g., using suture techniques that invert mucosa). tract (e.g., using suture techniques that invert mucosa).

The surgeon must carefully inspect the closure for leaks after repair. Also, the tissue The surgeon must carefully inspect the closure for leaks after repair. Also, the tissue that is used for closure must be viable, with adequate blood supply. The suture line must be free that is used for closure must be viable, with adequate blood supply. The suture line must be free of tension, and the surgeon must prevent dead space under the oral cavity using muscle flaps of tension, and the surgeon must prevent dead space under the oral cavity using muscle flaps from the neck, a myocutaneous flap, or other transposed viable tissue. from the neck, a myocutaneous flap, or other transposed viable tissue.

PREVENTION OF CAROTID ARTERY BLOWOUTPREVENTION OF CAROTID ARTERY BLOWOUT When a pharyngocutaneous fistula is anticipated, a When a pharyngocutaneous fistula is anticipated, a

planned pharyngostoma may be appropriate. The planned pharyngostoma may be appropriate. The pharyngeostoma must be positioned away from the pharyngeostoma must be positioned away from the carotid sheath, ideally in the midline. In addition, suction carotid sheath, ideally in the midline. In addition, suction catheter may be placed into this pharyngostoma to divert catheter may be placed into this pharyngostoma to divert pharyngeal sections and minimize the amount of pharyngeal sections and minimize the amount of drainage and soiling of the skin incisions. drainage and soiling of the skin incisions.

Prosthetic vascular grafts should not be used if infection Prosthetic vascular grafts should not be used if infection is present or when there is likelihood of a postoperative is present or when there is likelihood of a postoperative pharyngocutaneous fistula. One can create a controlled pharyngocutaneous fistula. One can create a controlled pharynogostoma in these instances to avoid this serious pharynogostoma in these instances to avoid this serious complication. complication.

It has been documented that the vasa vasorum of the It has been documented that the vasa vasorum of the carotid artery is crucial in determining the viability of the carotid artery is crucial in determining the viability of the carotid artery and of the dermal graft placed over the carotid artery and of the dermal graft placed over the carotid. carotid.

REFERENCES 1. CLINICALLY ORIENTED ANATOMY – MOORE DALLEY 2.TEXTBOOK OF ANATOMY HAMLINTON 3.GRAYS ANATOMY 4.TEXT BOOK OF EMBRYOLOGY I.B SINGH 5.A.D.A.M.S. STUDENTS ANATOMY ATLAS 6 S.N.SAHANA 7.ANATOMY FOR SURGEONS HOLLINSHIELD 8.COMPLICATIONS IN HEAD &NECK SURGERIES KABAN 9.HUMAN ANATOMY B.D CHAURASIA 10.CARMIRE D. CLEMETE ANATOMY ATLAS

arterial supply of head & neck

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