Sensory Nerves of the face

The skin of the face is supplied by branches of the trigeminal nerve, except for a small area over the angle of the mandible & parotid gland which is supplied by the great auricular nerve of the C2 &C3 ( cervical plexus) . These nerves not only supply the skin but also supply proprioceptive fibers to the underlying muscles of the face.

A- Ophthalmic nerve: it supplies the skin of the forehead, upper eye lid , conjunctiva and the side of the nose down to the tip. It has 5 branches

1 -The lacrimal nerve: To the skin & conjunctiva of the lateral side of the upper eyelid.

2-The supraorbital N. : it winds around the U. margin of the orbit at supraorbital notch.

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3- Supratrochlear N. : Winds & supply the skin & conjunctiva.

4- Infratrochlear N : It leaves the orbit below the pulley of the superior oblique muscle

5- External nasal N. : It leaves the nose by emerging between the nasal bone & upper n nasal cartilage.

B. Maxillary nerve: To the skin of the lateral side of the orbit , of the lower eyelid, cheek , upper lip and the posterior part of the side of the nose. It gives 3 As.

1- Infraorbital N. : It is a direct continuation of the maxillary nerve. It appears on the f face through the infraorbital foramen. To skin of the lower eyelid, c cheek, side of the nose and the upper lip.

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2 -Zygomaticofacial N. : It supplies the skin over the prominence of the cheek.

3 -Zygomaticotemporal N. : It supplies the skin over the temple.

C. Mandibular Nerve : It has 3 branches. It supplies the skin of the lower lip, lower part of the face, temporal region and the auricle.

1 -Mental N. : Emerges from the mental foramen. To lower lip & chin.

2 -Buccal N. : Emerges from beneath the anterior border of the masseter. To small area of the cheek.

3 -Auriculotemporal N. : Ascends from the upper border of the parotid gland between the superficial temporal vessels and the auricle. It supplies the skin of auricle; external auditory meatus; outer surface of the tympanic membrane and the skin over

the scalp above the auricle .

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Facial Nerve

As it comes out from its exit of the skull ( stylomastoid foramen ) it gives rise to the posterior auricular nerve which ascends behind the ear & supplies the posterior & superior auricular muscles & the occipital belly of occipitofrontalis.Then It runs forward within the substance of the parotid salivary gland & divides into its 5 terminal branches 1- Temporal N. : It emerges from the upper border of the gland & supplies the anterior & superior auricular muscles; frontal belly of the occipitofrontalis; orbicularis oculi and

corrugator supercilii ( O. superciliary arch & In. skin of eyebrow ) .

2 -Zygomatic N. : It emerges from the anterior border of the gland & supplies the orbicularis oculi.

3 -Buccal N. : It emerges from the anterior border of the gland below the parotid duct. It supplies the buccinator muscle & the muscles of the upper lip & nostril.

4 -Mandibular N. : It emerges from the anterior border of the gland & supplies the muscles of the lower lip.

5 -Cervical N. : It emerges from the lower border of the gland & passes forward in the neck below the lower margin of the body of the mandible. It supplies platysma & the depressor anguli oris muscle.

N.B. The proprioceptive nerve fibers ( in Ms, joints, and tendons which provides awareness of posture & movement ) of the facial muscles leave the branches

of the facial nerve & communicate with branches of the trigeminal nerve .

Arterial Supply

1- The superficial temporal A. It arises in the substance of the parotid gland as the smaller branch of the external carotid artery. It ascends from the upper end of the parotid gland in front of the auriculotemporal

nerve & auricle .

Branches: It gives rises to the Transverse facial artery: It arises within the parotid gland. It runs forward across the cheek

just above the parotid duct .

2 -The supraorbital & supratrochlear AS:

They are branches from the ophthalmic artery. They supply skin of the forehead.

3- Facial Artery

It arises from the external carotid artery. It arches upward over the submandibular gland. It curves around the inferior margin of the body of the mandible at the anterior border of the masseter muscle ( here pulse can be felt ). It runs upward in a tortuous course toward the angle of the mouth. It is covered by platysma & risorius muscles. It then ascends deep to the zygomaticus muscles & levator labii superioris muscle. It runs along medial side of the nose till medial angle of the eye, where it anastomoses with the

terminal branches of the ophthalmic artery.

Branches of the facial artery:a. submental A: .

It arises at the lower border of the body of the mandible. It supplies the skin of the chin & lower lip.

b. Inferior labial A: . It arises near the angle of the mouth. It

runs medially in the lower lip to anastomoses with the opposite side .c. Superior labial A: .

It arises near the angle of the mouth. it runs medially in the upper lip & gives branches to the septum & ala of the

nose. d. Lateral nasal A: .

It arises alongside the nose. It supplies the skin on the side & dorsum of the nose.

4 -Infraorbital A. : It is a continuation of the maxillary artery.

5 -Mental A. : It is a branch from the inferior alveolar artery of the maxillary.

6 -External nasal A. : It is the terminal branch of the anterior ethmoidal artery of the ophthalmic artery.

Venous Drainage

1 -The facial vein: it is formed at the medial angle of the eye by the union of the supraorbital & supratrochlear veins. It descends behind the facial artery to the lower margin of the body of the mandible. It crosses superficial to the submandibular gland. Then it joins the anterior division of the retromandibular vein. It crosses the carotid sheath then ends by draining into the internal jugular vein. Its Tributaries: a. Tthat correspond to the branches of facial artery. B .It joins to pterygoid venous plexus by the deep facial vein. C .It joins to cavernous sinus by the superior ophthalmic vein through the supraorbital vein. So infection from the face can spread to cavernous sinus.

2 -Transverse facial vein: It joins the superficial temporal vein within the parotid gland .

Lymph Drainage

1 -Lymph from the forehead & the anterior part of the face drains into

the submandibular lymph nodes .

2 -Buccal lymph nodes may be present along the course of the previous vessels.

3 -Lymph vessels which drain the lateral part of the eyelids & lateral part of the face are end in the

parotid lymph nodes .

4 -The central part of the lower lip & skin of the shin are drained into the submental lymph nodes.

Clinical notes of the face

1 -Blood supply of the facial skin: It is profuse so it is rare in plastic surgery for skin flaps to necrose.

2 -Facial arteries & Taking the patient’s pulse:

A. The superficial temporal artery as it crosses the zygomatic arch in front of the ear.

B. The facial artery as it winds around the lower margin of the mandible at the anterior margin of the masseter. It is used by the anesthetist to take the patient’s pulse.

3 -Facial Infection & cavernous sinus thrombosis:

The area of the skin bounded by the nose; eye and the upper lip is called the dangerous zone or area. A boil in this region can cause thrombosis of the facial vein which spread to the supraorbital vein then to the superior ophthalmic vein then to the

cavernous sinus .