the-scalp-meninges.ppt
DESCRIPTION
The-SCALP-MeningesTRANSCRIPT
The SCALP The SCALP & &
Cranial Meninges Cranial Meninges
done by : C.W.Tdone by : C.W.T
SCALPSCALP
The skin & subcutaneous tissue that covers the cranial vault
Extent:
sup. Nuchal lines (post.)
Supraorbital margins (ant.)
Zygomatic arches (lat.)
5 layer:
indicated by its letters
S: Skin
thin except?? “Occipital part”
many hair follicles & ? “sabaeceous glands “
rich in bld. Supply
C: Connective tissue
thick, dens C.T. septa
& fat lobules
rich in bld. Supply
* Bld. Vessels of scalp are running within this layer
A: Aponeurosis (flat tendon)
Epicranial aponeurosis
Galea Aponeurotica
strong tendinous sheet
provides attachment for:
occipitofrontalis m.
& ?? Laterally
“To the temporal fascia”
*1st 3 layers move together as one unit & called:
Scalp proper
L: Loose C.T.
has many potential spaces
sponge like layer
* allows free movement of scalp proper over bone.
P: Periosteumouter C.T. layer that surrounds the bones of calvaria
firmly attached to the bone
Innervations to The ScalpInnervations to The ScalpAnt.:
Supratrochlear & Supraorbital n.
(from ??) “ophthalmic n. (v1)”
Lat.:
Zygomaticotemporal n. (from?)
“ maxillary n. (v2)”
Auriculotemporal n. (from?)
“ maxillary n. (v2)”
Post.:
lesser occipital n.
(C2, ant. ramus)
Greater occipital n.
(C2, post. ramus)
Arteries of The ScalpArteries of The ScalpIn Which Layer?In Which Layer?
Ant.:Supratrochlear &
Supraorbital a. (ICA)
Lat.:Superficial temporal a.(ECA)
Post.:Post. Auricular a.Occipital a.(ECA)
* Scalp is an area of anastomosis between branches of ICA & ECA
Clinical: Injuries to The ScalpClinical: Injuries to The Scalp
* The scalp is one of the richest areas of bld. Supply in the body.
2 Sources: ECA & ICA
Small inj. to the scalp can result in sever prolonged bleeding
Due to:
1. rich blood supply
2. separation of vessel ends
by C.T. Septa & the aponeurosis
Rx.: suturing the injury
Scalp InfectionsScalp Infections
- Pus or blood spreads easily in The loose connective tissue layer of SCALP (Danger area of scalp)
- Infection or fluid in this layer (pus or bld.) cannot pass posteriorly or laterally, WHY??Post.: “nuchal lines” Lat.: “temporal lines”
- instead, Infection or fluid in this layer (pus or bld.) can spread either:anteriorly eyelids & root of nose black eye or Ecchymosis
into the cranial cavity through emissary veins meninges
The Cranial MeningesThe Cranial Meninges
3 layers of C.T., that:
1. protect the brain
2. provide supporting framework for a. & v.
3. enclose fluid-filled cavity (CSF)
3 layers:Dura materArachnoid materPia mater
Dura Mater
most external part
double layered membrane
2 layers:
ext. periosteal layer
(periosteum of calvarian bones)
Int. meningeal layer
- tough, thick fibrous membrane
continues at F. magnum to SC
* Brain Venous Sinuses are located between periosteal & meningeal layers of dura
Dural ReflectionsDural Reflections
Foldings of internal meningeal layer between brain compartments (septa) to restrict the rotatory displacement of the brain (fxn.)
4 main reflections:
falx cerebri
falx cerebelli
tentorium cerebelli
sellar diaphragm
Arachnoid MaterArachnoid Mater
Thin, intermediate layer that attaches to pia mater through web-like arachnoid trabeculae
Avascular layer
Held against dura by pressure of CSF
Subarachnoid space:
between arachnoid & pia
contains: arachnoid trabeculae & Cerebrospinal fluid (CSF)
Pia MaterPia Mater
Very thin & delicate membrane that is highly vascularized
Adheres to brain surface & follows its contours
Meningeal SpacesMeningeal Spaces
Epidural Space:
between dura & bone
not present normally
happens pathologically
(as hemorrhage)
Subdural Space:
between ? “arachnoid mater and dura mater”
not present normally
Subarachnoid Space:
a real space
contains CSF
Arterial Supply to Meninges Arterial Supply to Meninges (Dura & Calvaria)(Dura & Calvaria)
Middle Meningeal a. & Accessory Meningeal a.:
Main meningeal artery
From??” it is the third branch of the first part (retromandibular part) of themaxillary artery , the largest branche and one of the two terminal branches of the external carotid artery ”
Pass through?? “foramen spinosum”
2 Anterior meningeal a.:
From ethmoidal a. from ?? “from the ethmoidal artery which is also come from the theobthalamic a. which is branch of ICC”
4 Post. Meningeal a.:
2 from ascending pharyngeal a.
Pass through ?? one pass through 1.hypoglossal canal and the other from the 2.ugular (at the lower part of petrous part of temporal bone).
& 2 smaller branches from??one from the vertebral a.pass through 3.foramen magnum and the fourth post meningeal a. from the occipital a. which pass through the 4.mastoid foramen.
Clinical: Epidural HemorrhageClinical: Epidural Hemorrhage
Due to injury to a meningeal artery
middle meningeal a. (pterion)
Bld. Collects between:bones of clavaria & periosteal layeror periosteum & meningeal layers
Complications: bld. Mass compress the brain loss of consciousness & coma
Rx.: draining bld. & closure of the artery (ligation)
Read the clinical note in your textbook “Intracranial Hemorrhage”
Dural Venous SinusesDural Venous Sinuses
Blood filled spaces within dura matter that lined with endothelium and drain all bld. from brain and meninges.
Location: Between the periosteal and meningeal layers of dura,where dural infoldings attach.
Main :Sup. Sgittal sinusInf. Sagittal sinusStraight sinusTransverse sinus (2)Sigmoid sinus (2) IJV Cavernous sinus (2):venous plexus lat. to sella turcicaReceives sup. & inf. Ophthalmic v.From the orbit