SCALP

P.RavishankarSenior Lecturer

Dept.of AnatomySRM Dental College

ChennaiIndia

SCALP

• Definition

• Extent

• Layers

• Nerve supply

• Blood supply

• Clinical Anatomy

• Definition:-

Soft tissue covering the cranial vault

• Extent:-

Anteriorly:- Supra orbital margin

Posteriorly:-External occipital protuberance

& Superior nuchal line

Laterally:-Superior temporal line

Layers of SCALP

Skin

Connective tissue

Aponeurosis

Loose areolar tissue

Pericranium

1. Skin

Thick and hair bearing and contains numerous sebaceous glands

2. Superficial fascia

• Dense fibro- fatty connective tissue.

• Firmly attached to the skin and the aponeurosis.

• Numerous arteries, veins and nerves.

• Free anastomosis between the ICA an ECA branches.

3. Epicranial Aponeurosis(Galea Aponeuritica)

• A thin tendinous sheet that unites the occipital and frontal bellies of the occipitofrontalis muscle.

• The subaponeurotic space: potantial space beneath the aponeurosis.

4.Loose areolar tissue

Extension

• Anteriorly:- Eyelids

• Posteriorly:- Highest and superior nuchal line

• Laterally:- Superior temporal line

• Dangerous area of scalp

connect the superficial veins of the scalp with the diploic veins of the skull bones and with intracranial venous sinuses

Pericranium

• Modified periosteum

• Loosely attached to bones but firmly attached to sutures

Nerve supply to scalpIn front of auricleSensory

• Supratrochelar br.of Frontal nerve

• Supraorbital br. of frontal nerve

• Zygomatiotemporal br.ofZygomatic nerve

• Auriculotemporal nerve,br.ofMandibular nerve

Motor

• Temporal br. Of Facial nerve

Behind the auricle

Sensory

• Posterior division of great auricular nerve from cervical plexus(C2,C3)

• Lesser occipital nerve from cervical plexus(C2)

• Greater occipital nerve(C2dorsal ramus)

• Third occipital nerve(C3 dorsal ramus)

Motor

• Posterior auricular br.of facial nerve

Blood supply to scalp

Front of auricle

• Supratrochelar vessels

• Supraorbital vessels

• Superficial temporal vessels

Behind the auricle

• Posterior auricular vessels

• Occipital vessels

Clinical anatomy

• Surgical layers of scalp:-first 3 layers of scalp

• Sebaceous cyst are common in skin layer

• The wounds of scalp don’t gape unless it is cut transversely – because the aponeuroticlayer is tightly attached in the anteroposterior direction of occipitio-frontalis muscle

Clinical anatomyBlack eye:-

• Black discoloration of skin around eye

• Blood and fluid collection in the upper eye lid

• Blood accumulate to upper eyelid due attachment of frontalis muscle

Black eye

Safety-valve hematoma:-

• Fracture of cranial vault in children may associate with tearing of duramater and pericranium,in such cases blood from intracranial hemorrahage communicate with subaponeurotic space of scalp through the fracture line

• The sign of cerebral compression doesn’t occurs until subaponeurotic space is filled

• Therefore blood collection in the fourth layer is called safety –valve hematoma

Dangerous layer of scalp

• Blood and pus freely tend to collect in this layer ,if pus collects in this layer the infection may travel readily along the emissary veins into the intracranial venous sinuses.

• Cephalhematoma:-

Subperiosteal collection of blood

• Caput succedaneum:-

Subcutaneous edema .it takes place during the passage of head through the birth canal due interference of venous return