DEFINITION

It is the soft tissue covering the Norma skull) .

• Verticalis ( vault of the

EXTENSION

It extends from the superciliary arches anteriorly to the external occipital protuberance posteriorly.

Laterally , it is zygomatic arch .

• continuous to the •

S C A

LAYERS

The scalp is formed of (Five) layers.

They can be defined by the word itself: • S

–

Skin .

• C

–

Connective tissue .

A

–

Aponeurotic layer .

• • •

LAYERS

L

–

Loose tissue.

• connective P Periosteum • L P

SCALP PROPER

It is the first three layers that are tightly held together to form a single unit.

• It is the tissue torn away during serious scalping injuries .

•

SKIN

It is thick hairy with numerous sebaceous and sweat glands.

Obstruction of the ducts of the secretions form Sebaceous cysts . They move with the scalp.

• sebaceous glands by • •

CONNECTIVE TISSUE

It is a fibro-fatty layer which is adherent to the skin and to the underlying aponeurosis by fibrous septa.

It is richly supplied with vessels and nerves embedded within it.

• •

APONEUROTIC LAYER

It is a thin and tendinous sheet that unites the frontal and occipital bellies of occipitofrontalis muscle .

It is attached laterally to the • temporal fascia .

•

OCCIPTOFRONTALIS MUSCLE

It has a frontal belly An anteriorly, occipital belly and an aponeurotic tendon • (galea aponeurotica) connecting the two bellies.

• posteriorly,

FRONTAL BELLIY It arises from the anterior part of the aponeurosis. It is inserted into the skin of the eye brows.

• •

FRONTAL BELLY

It elevates the the face a surprised looking and produces transverse wrinkles of the forehead.

• eyebrows giving

OCCIPTAL BELLY It arises from the on the occipital bone. • highest nuchal lines It passes superiorly to be inserted into the aponeurosis.

• •

NERVE SUPPLY It is through the of the • terminal branches Facial nerve .

The frontal belly is supplied by the temporal branch .

The occipital belly is supplied by the posterior auricular branch.

• •

LOOSE AREOLAR TISSUE

It occupies the subaponeurotic space. • It contains few arteries and the important emissary veins .

•

DANGEROUS LAYER

The (4 th ) layer of the scalp is the dangerous layer because pus or blood spreads easily in it.

• • Infection in this layer can spreads into the bones through the diploic veins causing osteomyelitis

SCALP INFECTIONS

It can spread through the • emissary veins to the intracranial venous sinuses to cause Venous Sinus thrombosis.

SCALP INFECTIONS

An infection in the scalp can not extend posteriorly into the neck because of the attachment of occipitalis muscle to the occipital and temporal bones.

•

SCALP INFECTIONS

Nor laterally because of • attachment of the aponeurosis to the temporal fascia.

SCALP INFECTIONS

An infection or fluid can spreads only into the eye lids and the root of the nose because of the attachment of the skin and not to the bone.

• the frontalis into

PERICRANIUM

It is the deepest layer. It is the periosteum on the outer surface of the calvaria.

• At the becomes continuous with the periosteum on the outer surface of the bones. sutures it • •

SENSORY NERVE SUPPLY

It is from two main sources : Trigeminal nerve.

• Cervical nerves 3 RD ).

(2 ND • & • Depending on whether it is anterior or posterior to the ears.

•

ANTERIOR TO THE EAR

(A) Ophthalmic nerve: • 1.Supratrochlear

It exits from the orbit.

• • It ascends • superiorly to supply the forehead and scalp as far as the midline (vertex).

ANTERIOR TO THE EAR

2. Supraorbital: • It exits from the orbit through the • supraorbital notch.

It passes superiorly to the scalp as far as the vertex.

•

ANTERIOR TO THE EAR

(B) Maxillary nerve : • 3. • Zygomaticotemporal nerve: It exits through a zygomatic bone.

• small foramen in the It supplies a small anterior area of the temple.

•

ANTERIOR TO THE EAR

: (C) Mandibular nerve 4. Auriculotemporal nerve: It passes just • anterior to the ear.

It supplies the scalp over the temporal region.

• • •

POSTERIOR TO THE EAR

1. Great auricular It supplies a small area posterior to the scalp.

• 2. Lesser occipital: it supplies the area posterior and superior to the scalp.

• •

POSTERIOR TO THE EAR

3. Greater occipital of C 2).

• (posterior ramus 4. Third occipital of C 3).

• (posterior ramus

ARTERIAL SUPPLY

The scalp has a rich blood supply.

The arteries take origin from: External carotid artery. • • Ophthalmic artery.

• The arteries freely anastomose with each other. • •

OPTHALMIC ARTERY

1. Supratrochlear .

2. Supraorbital.

• • They accompany the corresponding nerves to supply the scalp as far as the vertex. •

EXTERNAL CAROTID ARTERY

From the posterior aspect: 1. Posterior auricular : • It is the smallest branch.

It supplies the scalp posterior to the ear.

• • •

EXTERNAL CAROTID ARTERY

2.Occipital : • It accompanies the • greater occipital nerve.

It passes through the musculature of the back • It supplies a large area of the back of the scalp.

•

EXTERNAL CAROTID ARTERY

3. Superficial temporal artery: It is the smaller external carotid.

• terminal branch of the It divides into anterior and posterior branches.

It supplies almost the entire lateral aspect of the scalp.

• • •

VEINS OF THE SCALP

Supratrochlear & supraorbital veins: • They drain the anterior part of the scalp.

They communicate with the ophthalmic veins in the orbit.

• • Inferiorly they participate in the formation of the angular vein (upper tributary of the (Facial vein ).

•

VEINS OF THE SCALP

Superficial temporal vein: It drains the entire lateral area of the scalp.

Inferiorly, it joins the maxillary vein to form the Retromandibular vein.

• • •

VEINS OF THE SCALP

Posterior auricular vein: It drains the area • posterior to the ear.

• It unites with the vein to form the • posterior division of the retromandibular External Jugular vein.

VEINS OF THE SCALP

Occipital vein: • It drains into the plexus.

• suboccipital venous The plexus drains into the vertebral jugular vein.

• veins or the internal

VEINS OF THE SCALP

Veins of the scalp are connected to the Diploic veins and to the Intracranial venous sinuses through the valveless Emissary veins.

LYMPH DRAINAGE

Lymph vessels • follow the arteries.

From the anterior part and forehead drain into : Submandibular nodes .

•

LYMPH DRAINAGE

Lateral part (above the ear) to: Superficial parotid (preauricular).

• • Lateral part (behind the ear) to: Mastoid nodes . • Back of the scalp to: occipital nodes .

• •

SCALP LACERATIONS

Wounds of the scalp bleed profusely because of: • 1. The abundant arterial anastomoses.

•

SCALP LACERATIONS

2. Arteries do not retract when lacerated because they are held open by the dense connective tissue in layer (2).

• Local pressure the only way to stop bleeding.

is •

SCALP LACERATIONS

Deep scalp wounds needs to be sutured because they gape widely when the is divided. • epicranial aponeurosis • This because of the tension of the aponeurosis produced by the tone of the occipitofrontalis muscle.