Skull and ScalpBy

Dr Manah Chandra Changmai MBBS MS

Study of the skull is done by looking into

a.Norma verticalis

b.Norma frontalis

c.Norma occipitalis

d.Norma lateralis

e.Norma basalis

Skull

Skull

Norma lateralisNorma frontalis

Norma frontalis

Norma lateralis

Changes in scalp before and after birth

Norma verticalis

Sutures of the scalp

Norma occipitalis

Pterion

Asterion

Norma basalis

The soft tissue that extends across the calvariaOf the skull

The scalp extends from :

The top of the forehead in front to the superior nuchal line behind.

Laterally it projects down to the zygomatic arch and external acoustic meatus.

It consists of five layers: a. skin b. subcutaneous tissuec. occipitofrontalis (epicranius) aponeurosis (galea aponeurotica) d. subaponeurotic areolar e. pericranium

Scalp

The skin of the scalp contains the hair and associated glands.

There are many sebaceous glands

The scalp is the commonest site for sebaceous cysts.

1. Skin

2. Dense connective tissue

Consists of close network of fibrofatty tissue.

Connects firmly the overlying skin and underlyinggalea aponeurotica and epicranius muscle.

Contains large blood vessels and nerve of the scalp

The blood vessels when torn lead to heavy bleeding.

3.Epicranius muscle and its aponeurosis

Includes the occipitofrontalis muscle and a variable slip ofTemporoparietalis muscle.

Occipitofrontalis

Consists of paired occipitalis bellies behind and frontal belliesIn the front.

Occipital bellies

Each belly arise from lateral two third of superior nuchal lineof occipital bone and from mastoid bone.

The two bellies are seperated by considerable interval.

It is supplied posterior auricular branch of facial nerve.

Frontal bellies

They donot have bony origin

Approximated to its other in the median plane.

Each belly arise from subcutaneous tissue of theeyebrow and nose.

Behind the muscle blend with galea aponeurotica infront of coronal suture.

It is supplied by temporal branch of facial nerve.

3. Galea aponeurotica or epicranial aponeurosis

Sheeth of fibrous tissue that connects occipital andfrontal bellies.

Behind : it is attached to the extenal occipital protruberance in between the two occipital bellies.

Front : it blends with with subcutaneous tissue and root of the nose in between the frontal bellies

On each side: It passes over the temporal fascia and attached to the zygomatic arch.

4. Loose subaponeurotic tissue or areolar tissue layer

Consists of loose areolar tissue and forms aspace below galea aponeurotica.

It consists of emissary veins which communicatesveins of the scalp and intracranial dural venous sinus

Infection of this layer spread readily into the intracranialvenous sinus through emissary veins.

Injury to this layer lead to black eye.

Also called the dangerous layer of the scalp

Areolar tissue layer

Black eye

5. Pericranium

Outer perioteum of the skull

Loosely covers the bones except at the sutural line

At the sutural line it is continous with the endocranium

Nerve supply of the scalp

Ten nerves supply the scalp

Five nerves infront of auricle and five nerves behind.

Nerves infront of auricle ( from before backwards )

1.Supra trochlear ( sensory ): opthalmic division of trigeminal nerve.2. Supra orbital nerve ( sensory ): opthalmic division of trigeminal nerve.3. zygomatico-temporal nerve ( sensory ): maxillary division of trigeminal nerve.4. Temporal branch of facial nerve ( motor )5. Auriculo temporal nerve ( sensory )

Nerves behind the auricle ( before backwards )

1.Posterior branch of great auricular nerve ( sensory )2.Posterior auricular branch of facial nerve ( motor )3.Lesser occipital nerve ( sensory )4.Greater occipital nerve ( sensory )5.Third occipital nerve ( sensory )

Nerve and arterial supply of scalp

Venous drainage of the scalp

Thank you