The soft tconcern envelope of the cranial vault is dubbed the scalp. The scalp exoften tends from the exterior occipital protuberance and also superior nuchal lines to the supraorbital margins. The scalp consists of 5 layers (watched in the image below): the skin, connective tconcern, epicranial aponeurosis, loose areolar tconcern, and also pericranium. The initially 3 layers are bound together as a solitary unit. This single unit have the right to move along the loose areolar tproblem over the pericranium, which is adherent to the calvaria. <1, 2, 3, 4>
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The skin of the scalp is thick and also hair bearing and also contains plenty of sebaceous glands. As an outcome, the scalp is a prevalent site for sebaceous cysts.
Connective tworry (superficial fascia)
The superficial fascia is a fibrofatty layer that connects skin to the underlying aponeurosis of the occipitofrontalis muscle and provides a passageway for nerves and blood vessels. Blood vessels are attached to this fibrous connective tissue. If the vessels are reduced, this attachment avoids vasospasm, which could cause profusage bleeding after injury.
Epicranial aponeurosis (galea aponeurotica)
The epicranial aponeurosis is a thin, tendinous structure that provides an insertion site for the occipitofrontalis muscle. Posterolaterally, the epicranial aponeurosis attachment extends from the premium nuchal line to the exceptional temporal line. Laterally, the epicranial aponeurosis continues as the tempdental fascia. Anteriorly, the subaponeurotic room exoften tends to the upper eyelids because of the lack of a bony insertion. This loose areolar tproblem offers a potential subaponeurotic space that allows fluids and blood to pass from the scalp to the upper eyelids.
Loose areolar tissue
Areolar tissue loosely connects the epicranial aponeurosis to the pericranium and permits the superficial 3 layers of the scalp to move over the pericranium. Scalp flaps are elevated alengthy a relatively avascular aircraft in craniofacial and neurosurgical procedures. However before, particular emissary veins traverse this layer, which connects the scalp veins to the diploic veins and intracranial venous sinsupplies.
The pericranium is the periosteum of the skull bones. Alengthy the suture lines, the pericranium becomes constant via the endosteum. A subperiosteal hematoma, therefore, creates in the shape of the skull bones.
The occipitofrontalis muscle is composed of 2 occipital bellies and also 2 frontal bellies. The occipital bellies aclimb from the premium nuchal lines on the occipital bone. The frontal bellies originate from the skin and also superficial fascia of the top eyelids. The occipital and also frontal bellies insert right into the epicranial aponeurosis.
Each occipital belly is innervated by the posterior auricular branch of the facial nerve, and each frontal belly is innervated by the frontal branch of the facial nerve. The frontal bellies have the right to raise the eyebrows.
The adhering to 6 sensory nerve branches of either the trigeminal nerve or the cervical nerve supply the scalp (see the picture below):
Sensory innervation and arterial supply of the scalp (From Snell RS, Clinical Anatomy for Medical Students, fifth ed)
Supratrochlear nerve - A branch of the ophthalmic department of the trigeminal nerve; this nerve offers the scalp in the medial airplane at the frontal region, as much as the vertex
Supraorbital nerve - Also a branch of the ophthalmic department of the trigeminal nerve; this nerve gives the scalp at the front, lateral to the supratrochlear nerve circulation, up to the vertex
Zygomaticotempdental nerve - A branch of the maxillary division of the trigeminal nerve; it provides the scalp over the holy place region
Auriculotempdental nerve - A branch of the mandibular division of the trigeminal nerve; it offers the skin over the temporal region of the scalp
Lesser occipital nerve - A branch of the cervical plexus (C2); it offers the scalp over the lateral occipital region
Greater occipital nerve - A branch of the posterior ramus of the second cervical nerve; it supplies the scalp in the median airplane at the occipital area, as much as the vertex
The frontal branch of the facial nerve supplies the frontal bellies of the occipitofrontalis muscle, and the auricular branch of the facial nerve gives the occipital bellies of the muscle.
Sensory innervation and also arterial supply of the scalp (From Snell RS, Clinical Anatomy for Medical Students, 5th ed)
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