Scalp Flashcards
The scalp is the part of the head that extends from
the superciliary arches anteriorly to the external occipital protuberance and superior nuchal lines posteriorly
Laterally the scalp continues inferiorly to the
Zygomatic arch
“SCALP”
Skin Connective tissue Aponeurosis Loose areolar tissue Pericranium
Scalp proper
SCA
from which head hair grows; richly supplied with blood vessels
Skin
a thin layer of fat and fibrous tissue lies beneath the skin
Connective tissue
epicranial aponeurosis (or galea aponeurotica); a tough layer of dense fibrous tissue which runs from the frontalis muscle anteriorly to the occipitalis posteriorly connecting the two
Aponeurosis
provides an easy plane of separation between the upper three layers and the pericranium
Loose areolar connective tissue
“Danger Zone” because of the ease by which infectious agents can spread through it to emissary veins which then drain into the cranium
Loose connective tissue
contains the major blood vessels of the scalp, which bleed profusely upon injury, partly due to the absence of venous valves found in the circulation below the neck
Loose areolar tissue
the periosteum of the skull bones and provides nutrition to the bone and the capacity for repair
Pericranium
may be lifted from the bone to allow removal of bone windows (craniotomy)
Pericranium
clinically important layer
Aponeurosis
Scalp lacerations through this layer mean that the “anchoring” of the superficial layers is lost and gaping of the wound occurs; this requires suturing
Aponeurosis
the muscle of the scalp
Epicranial aponeurosis
Action of the frontal portion of the epicranial aponeurosis
lies across the forehead and raises the eyebrows and wrinkles the forehead
Action of the occipital portion of the epicranial aponeurosis
located at the base of the skull and draws the scalp backwards
thin quadrilateral muscle that is intimately adherent to the superficial fascia
Frontalis
Action of the frontalis muscle
Draws the scalp forward, raises eyebrows, and wrinkles the skin of the forehead horizontally
Blood supply of the scalp
5 pairs of arteries, 2 from the internal carotid and 3 from the external carotid
Located at midline forehead; is a branch of ophthalmic branch of the internal carotid artery
Supratrochlear artery
lateral forehead and scalp as far up as the vertex; is a branch of ophthalmic branch of the internal carotid artery.
Supraorbital artery
gives frontal and parietal branches to supply much of the scalp
superficial temporal artery
runs from posteriorly to supply much of the back of the scalp
Occipital artery
a branch of the external carotid artery , ascends behind the auricle to supply the scalp above and behind the auricle
Posterior auricular artery
scalp bleeding is predominantly arterial, because of two reasons:
- in the erect position the venous pressure is extremely low
- the vessels do not retract when lacerated because the connective tissue in which they are found prevents retraction
The scalp is innervated by the following
- Supratrochlear nerve and the supraorbital nerve from the ophthalmic division of the trigeminal nerve
- Greater occipital nerve (C2) posteriorly up to the vertex
- Lesser occipital nerve (C3) behind the ear.
- Zygomaticotemporal nerve from the maxillary division of the trigeminal nerve supplying the hairless temple
- Auriculotemporal nerve from the mandibular division of the trigeminal nerve
the part of the head that extends from the superciliary arches anteriorly to the external occipital protuberance and superior nuchal lines posteriorly
Scalp
