Scalp Dr. Ayat Eldomouky

Extention of the scalp

Anterior:- eyebrows.

Posterior:- superior nuchal line.

On each side:- Superior temporal line.

Layers of the scalp1. S= skin2. C= connective tissue3. A= aponeurosis4. L= loose areolar tissue5. P= pericranium (periosteum)The scalp is supplied by 5 arteries and drained

by 5 veins .

S

C

A

L

P

2- muscles of scalp

Occipito-frontalis muscle:Origine:

1) Two frontal bellies: skin of forehead2) Two occipital bellies: highest nucal line

Insertion:

Into the epicranial aponeurosis

Nerve supply: facial nerve

(all muscles of facial expression are innervated by facial nerve)

Action

Tense the aponeurosisRaises the eyebrows and wrinkels the forehead

Nerve supply of the scalp

Infront of the auricle

5 nerves 4 sensory (V)One motor (facial )

Behind the auricle

5 nerves4 sensory( cervical

nerves)One motor( facial )

3rd occipital n.

G.Auricular n.

Sensory Nerves

3-Nerves of scalp

4- arteries of scalp

Arteries : 5 on each sidea) Supratrochlear a. (from ophthalmic a. of the I.C.A.)b) Supraorbital a. (from ophthalmic a. of the I.C.A.)c) Superficial temporal a. (from E.C.A.)d) Posterior auricular a. (from E.C.A.)e) Occipital a. (from E.C.A.)

Notice :1- The scalp has the richest cutaneous blood supply of the body.2- The scalp is a site of anastomosis between I.C.A. and E.C.A.3- The arteries come from the peripheries and anastomose freely in the scalp center→ surgically scalp flaps are reflected downwards.4- The scalp and face have no deep fascia.

Wound in the scalp is characterized by1- Profuse bleeding.2- Rapid healing.3- Gapping (the aponeurosis is under tension).4- Difficulty to ligate the bleeder due to the C.T. septa of the superficial fascia.5- Blood in the loose areolar C.T. layer may reach to the face → black eye.

Arteries of the Scalp

Supraorbital A.

Supratrochlear

Superficial temporal A.

Post.auricular A.

Occipital A.

5-veins of scalp

Veins : Correspond to the arteries:

1- Supratrochlear v . + 2- Supraorbital v. unite at the medial angle of the eye forming the facial v.

3- Superficial temporal v. : Enters the parotid gland and unites with the maxillary vein forming the retromandibular vwhich divides into ant. and post. divisions. The 2 divisions leave the lower end of the parotid gland.

4- Posterior auricular vein: Joins the post. division of retromandibular vein to form the external jugular vein.

5- Occipital vein: Descends to join the suboccipital venous plexus.

(C) Emissary Veins @ Definition: They are veins which connect the dural venous sinuses inside the cranial cavity with the veins outside the skull. @ Characters : 1. They are valveless and so the blood flows in them in both directions. 2. They pass through the foramina and fissures of the skull. 3. Some of them are constant while others may be present or absent. @ Function : equalize the venous blood pressure between the intracranial venous sinuses and the extracranial veins. @ Clinical importance : They can transmit infection from outside the skull (eg. Dangerous area of face) to the dural sinuses.

Emissary Vs.

The dangerous area of the scalp is the subaponeurotic space which is contains loose areolar tissue and emissary veins so infection in this area can spread into the intracranial tissue

Face

1- muscles of fascial expressionN.B: all muscles of facial expression are innervated by facial nerve

a- orbicularies oculi

Orbicularies oculi muscle:Origine & Insertion:

1) Orbital part: arises from the medial orbital margin and form a contineous circles around the orbital margin

2) Palpebral part: arises from the the medial palpebral ligament to be inserted into lateral palpebral raph

3) Lacrimal part: very small parts which surrounds the lacrimal sac

Nerve supply: facial nerve

(all muscles of facial expression are innervated by facial nerve)

Action

Firm closure of the eye the orbital partAnd gentil closure of the eye by the palpebral part

B- orbicularies orisIt is formed mainly from thr fibers of the biccinator muscle and the anguli oris ,Innervated by facial nerve

C-buccinator Origine:The upper fibers of the muscle arises from the maxilla and the lower fibers arises from the mandible The intermediate fibers arises from the pterygo-mandibular ligament

Insertion: The upper fibers inserted into the upper lipThe lower fibers inserted into the lower lipThe intermediate fibers decussate at the angle of the mouth

Nerve supply: facial nerve

(all muscles of facial expression are innervated by facial nerve)

ActionPress the cheek against the gumesProper closure of the angle of the mouth

C- Risorius “The grinning muscle” Inserts horizontally into the angle of the mouth there by retracting the angleSuperficial to buccinator