the scalp meninges e-learning

8/2/2019 The SCALP Meninges E-learning

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The SCALP&

Cranial Meninges

done by : C.W.T


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SCALP

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


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S: Skinthin except?? Occipital part many hair follicles & ? sabaeceous glands rich in bld. Supply

C: Connective tissuethick, dens C.T. septa& fat lobules

rich in bld. Supply

* Bld. Vessels of scalp are running within this layer


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A: Aponeurosis (flat tendon)Epicranial aponeurosisGalea Aponeurotica

strong tendinous sheet

provides attachment for:occipitofrontalis m.& ?? Laterally

To the temporal fascia

*1st 3 layers move together asone unit & called:

Scalp proper


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L: Loose C.T.has many potential spaces

sponge like layer

* allows free movement ofscalp proper over bone.

P: Periosteumouter C.T. layer that surroundsthe bones of calvaria

firmly attached to the bone


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Innervations 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 )


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Arteries of The ScalpIn 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


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Clinical: 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 bleedingDue to:

1. rich blood supply

2. separation of vessel endsby C.T. Septa & the aponeurosis

Rx.: suturing the injury


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Scalp Infections

- Pus or blood spreads easily in The loose connective tissue layerof SCALP (Danger area of scalp)

- Infection or fluid in this layer (pus or bld.) cannot pass posteriorlyor laterally, WHY??

Post.: nuchal lines Lat.: temporal lines

- instead , Infection or fluid in this layer (pus or bld.) can spreadeither:

anteriorly eyelids & root of nose black eye or Ecchymosis

into the cranial cavity through emissary veins meninges


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Dura Mater

most external partdouble 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


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Dural ReflectionsFoldings 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


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Arachnoid Mater

Thin, intermediate layer that attaches to pia mater throughweb-like arachnoid trabeculaeAvascular layer

Held against dura by pressure of CSF

Subarachnoid space:between arachnoid & pia

contains: arachnoid trabeculae & Cerebrospinal fluid ( CSF )


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Pia Mater

Very thin & delicate membrane that is highlyvascularized

Adheres to brain surface & follows its contours


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Meningeal Spaces

Epidural Space:between dura & bonenot present normallyhappens pathologically(as hemorrhage )

Subdural Space:between ? arachnoidmater and dura mater

not present normally

Subarachnoid Space:a real spacecontains CSF
http://en.wikipedia.org/wiki/Arachnoid_materhttp://en.wikipedia.org/wiki/Arachnoid_materhttp://en.wikipedia.org/wiki/Arachnoid_materhttp://en.wikipedia.org/wiki/Dura_materhttp://en.wikipedia.org/wiki/Dura_materhttp://en.wikipedia.org/wiki/Arachnoid_materhttp://en.wikipedia.org/wiki/Arachnoid_materhttp://en.wikipedia.org/wiki/Arachnoid_mater


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Arterial Supply to Meninges(Dura & Calvaria)

Middle Meningeal a. & Accessory Meningeal a.:

Main meningeal artery

From?? it is the third branch of the first part (retromandibularpart) of the maxillary artery , the largest branche and one of the twoterminal branches of the external carotid artery

Pass through?? foramen spinosum

2 Anterior meningeal a.:

From ethmoidal a. from ?? from the ethmoidal arterywhich is also come from the theobthalamic a. which is branch of ICC
http://en.wikipedia.org/wiki/Maxillary_arteryhttp://en.wikipedia.org/wiki/External_carotid_arteryhttp://en.wikipedia.org/wiki/Foramen_spinosumhttp://en.wikipedia.org/wiki/Foramen_spinosumhttp://en.wikipedia.org/wiki/External_carotid_arteryhttp://en.wikipedia.org/wiki/Maxillary_artery


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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 thefourth post meningeal a. from the occipital a. which pass through the4.mastoid foramen.


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the scalp meninges e-learning

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