Face and scalp

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Blood supply

The arteries of the face and scalp.

Arteries

  • derived mainly from the external carotid artery
  • with a contribution from the internal carotid artery

Facial artery

  • a branch of the external carotid artery
  • Enters the face from the neck by crossing the body of the mandible just anterior to the masseter
  • From this point, it follows a tortuous course, mostly deep to the muscles of facial expression, to the medial angle of the eye
  • Here it may anastomose with branches of the ophthalmic artery which emerge from the orbit
  • the facial artery gives branches to the face, lips and nose

Superficial temporal artery

  • a terminal branch of the external carotid artery
  • It emerges from deep to the upper border of the parotid gland
  • passes superiorly, in front of ear
  • It has branches that supply the face, ear, temple and scalp
  • Other arterial branches emerge on to the face with branches of sensory nerves

Veins

Veins of the head and neck.
  • accompany the arteries
  • They do not contain valves

Superficial temporal vein

  • accompanies the corresponding artery
  • originates in the scalp and passes deep to the parotid gland
  • Here, it joins the maxillary vein to form the retromandibular vein
  • The retromandibular vein may divide into
    • a posterior division which joins the posterior auricular vein, to become the external jugular vein
    • an anterior division which joins the facial vein in the neck, to form the common facial vein

Facial vein

  • originates at the medial angle of eye, where it communicates with ophthalmic veins of the orbit
  • The facial vein crosses the face behind the facial artery, into the neck, where it may join the anterior division of the retromandibular vein to form the common facial vein, which usually drains into the internal jugular vein
  • In the face, a deep facial vein (branch of the facial vein) may pass on the surface of the buccinator muscle into the infratemporal fossa, where it joins the pterygoid venous plexus
  • There is great variation in arrangement of the veins that drain the face, once they reach the neck.

Innervation

The nerves of the scalp, face, and side of neck.

Facial nerve (VII)

  • the terminal, motor part of the nerve emerges from the facial canal at the stylomastoid foramen
  • It gives branches to the stylohyoid and posterior belly of digastric muscles, before entering the parotid gland
  • There, it divides into a number of branches which radiate from the periphery of the gland to supply the muscles of facial expression
  • There are several cross-communications between the branches
Sensory areas of the head, showing the general distribution of the three divisions of the fifth nerve.

Trigeminal nerve

  • the skin of the face is supplied mainly by branches of the three divisions of the trigeminal nerve, except for an area over the angle of the mandible, parotid gland and ear, which is supplied by the great auricular nerve (C2, C3)

Ophthalmic nerve (V1)

  • the frontal and lacrimal nerves leave the orbit to supply the anterior scalp, forehead, upper eyelid
  • nasociliary branches supply the side of the nose via the nasal cavity

Maxillary nerve (V2)

  • the infraorbital and zygomatic branches are sensory to the area between the lower eyelid and the upper lip, as well as to a small part of the bony cheek and temple

Mandibular nerve (V3)

  • the mental, buccal and auriculo-temporal branches supply the chin, lower lip, cheek, ear and lateral part of the scalp.

Layers of the scalp

  • The scalp consists of five layers:
    1. Skin
    2. Connective tissue
    3. Aponeurosis (epicranial)
    4. Loose connective tissue
    5. Periosteum
  • Scalp wounds usually gape and bleed profusely, mainly because the muscles (occipitalis and frontalis) pull the aponeurosis apart, exposing the arteries to bleeding

Resources