The-SCALP-Meninges.ppt

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