Transcript
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
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