Scalp

Introduction

The hemorrhage from a scalp laceration or operation is profuse; it area has, the richest cutaneous blood supply of the body.

For this reason, extensive avulsions of the scalp are usually viable providing even a narrow pedicle remains attached to the surrounding tissues.

ScalpSoft tissue covering the cranial vault•It is hair bearing area of the skull•Extend from supra orbital margin anteriorly to external occipital protuberance & superior nuchal line posteriorly

On each side to superior temporal line

SCALP

S-Skin C-connective tissue

(superficial fascia) A-aponeurosis (galea

aponeurotica) L-loose areolar tissue P-pericranium

Skin Thick and hairy Firmly attached to

the epicranial aponeurosis through dense fascia

Abundance sebaceous glands

Sebaceous cyst are common

Skin

The skin of the scalp is richly supplied with sebaceous glands and is the commonest site in the body for sebaceous cysts.

A superficial infection of the scalp may spread via this system producing an osteitis of the skull, meningitis and venous sinus thrombosis.

Connective tissue Fibrous and dense containing blood vessels and

nerves Binds skin to subjacent aponeurosis Wounds bleed profusely as blood vessels are

prevented from retraction by fibrous tissue. Bleeding is stopped by applying pressure against the bone

Subcutaneous hemorrhage are not extensive since fascia is dense

Inflammation cause little swelling but are much painful

Aponeurosis

The aponeurotic layer is under tension because of its muscular component and retracts on the underlying loose layer when divided; a gaping scalp wound must, therefore, have extended at least through the aponeurosis.

Aponeurosis Anteriorly frontal belly and

posteriorly occipital belly of occipitofrontalis muscle

Frontal belly originate from skin of forehead and mingled with orbicularis oculi muscle

Occipital belly originate from lateral 2/3 of superior nuchal line

It gaps if cut transversely and should be stitched

Loose areolar tissue The layer of loose connective tissue

beneath the aponeurosis accounts for the mobility of the scalp on the underlying bone;

it is in this plane that the surgeon mobilizes scalp flaps, that machinery which has caught on to the hair avulses the scalp and that the Red Indians of bygone days scalped their victims.

Loose areolar tissue Blood or pus collecting in this loose

tissue tracks freely under the scalp but cannot pass into either the occipital or subtemporal regions because of the attachments of occipitofrontalis.

Fluid can, however, track forward into the orbits and this accounts for the orbital haematoma that may form a few hours after a severe head injury or cranial operation.

Loose areolar tissue Extends anteriorly into the

eyelids because frontalis has no bony attachment

Posteriorly to superior nuchal line

On each side to superior temporal line

Bleeding cause generalized swelling of scalp

Caput succedaneum

Loose areolar tissue

Called dangerous layer of scalp-emissary veins open here and carry any infections inside the brain (venous sinus)

Bleeding lead to black eye

Caput succedaneum in new born

Pericranium Is the periosteum of skull Loosely attached to

surface of bone but is firmly adherent to the sutures

Injury deep to it take the shape of bone (cephalhaematoma)

Scalping injury- should be replaced and stitched because healing is better cephalhaematoma

Caput succedaneum cephalhaematoma

Blood supply

Arteries Supratrochlear Supraorbital Superficial temporal Posterior auricular artery Occipital artery

Veins-follows the artery

Nerve supply

In front of auricle Supratrochlear n. Supraorbital n. Zygomaticotemporal n. Auriculotemporal n. Temporal branch of facial n.

Behind auricle Greater auricular n Lesser occipital n. Greater occipital n. Third occipital n. Post. Auricular branch of facial n.

Lymphatics

Anterior partPreauricular (parotid) gr. of lymph node

Posterior partPosterior (mastoid) gr. of lymph node

&occipital gr. of lymph node