Sensory Nerve Supply of the Face

Sensory Nerve Supply of the Face

• The face is supplied by branches of the trigeminal nerve, with three zones meeting at eyelid and mouth margins.
• The zones' arrangement is developmental, curving upwards from original horizontal lines extending from eye and mouth angles; the mandibular nerve originally covered the mandible.
• The cranial cavity expanding over the brain moves face skin, including beard skin to the temple and neck replacing it.
• The great auricular nerve supplies skin over the mandible angle and area above and in front of it, the only area not served by trigeminal nerve branches.
• Face muscles' proprioceptive fibers originate in these branches along with multiple junctions with facial nerve branches.
• The trigeminal nerve has three divisions (ophthalmic, maxillary, mandibular) each with specific cutaneous branches (see graphic).

Trigeminal Nerve Branches

• Ophthalmic Nerve: Five cutaneous branches—lacrimal, supraorbital, supratrochlear, infratrochlear, and external nasal.
  • Lacrimal: lateral upper eyelid skin.
  • Supraorbital: forehead and scalp.
  • Supratrochlear: middle forehead.
  • Infratrochlear: medial upper eyelid and nose bridge.
  • External nasal: middle external nose.
• Maxillary Nerve: Three cutaneous branches—infraorbital, zygomaticofacial, and zygomaticotemporal.
  • Infraorbital: lower eyelid, cheek, side/ala of nose, upper lip and labial gum.
  • Zygomaticofacial: overlying zygomatic bone skin.
  • Zygomaticotemporal: front temple skin.
• Mandibular Nerve: Three cutaneous branches—auriculotemporal, buccal, and mental
  • Auriculotemporal: external acoustic meatus, tympanic membrane, auricle, temple skin.
  • Buccal: cheek skin below zygomatic bone, between infraorbital nerve and great auricular nerve areas.
  • Mental: lower lip and labial gum.

Sensory Distribution "Onion Skin" Pattern

• Pain fibers in the trigeminal nerve follow a pattern where fibers from the front of the face synapse with cells at the highest (pontine) part of the spinal trigeminal nucleus.
• Concentric areas from mouth and nose regions synapse at successively lower nucleus levels.
• This "onion skin" arrangement for pain doesn't precisely correspond with cutaneous nerve distribution areas.

Blood Supply of the Face

• The facial artery, originating from the external carotid artery, has tortuous path, curving over the posterior digastric and masseter. Supplies the lips (important labial branches).
• Superficial temporal artery from external carotid supplies temple. Transverse facial artery branches across cheek.
• Ophthalmic artery from orbit supplies forehead via supraorbital and supratrochlear branches, and anastomoses with superficial temporal artery, connecting the internal and external carotid systems.

Venous Return and Drainage

• Venous return is predominantly superficial.
• Forehead veins (supraorbital & supratrochlear) converge at medial canthus forming the angular vein; eventually uniting with the facial vein.
• Facial vein joins the retromandibular vein below mandible. The retromandibular vein splits into ant/post branches, with the ant connecting with the internal jugular vein and post branch connecting with the external jugular vein.
• Temple blood drains into superficial temporal vein, which connects with the maxillary veins from pterygoid plexus to form the retromandibular vein.
• Deep venous anastomoses occur, and facial vein communicates with cavernous sinus, affecting "danger area" for facial infection.

Lymph Drainage of the Face

• Face drains into three superficial node groups (submental, submandibular, preauricular) from wedge-shaped blocks of tissue.
• Chin and tongue tip drain to submental nodes.
• A wedge of tissue (including parts of the nose, upper lip, lower face etc.) drains to submandibular nodes. The forehead and frontal sinuses are included in this wedge-shape area.
• Forehead, temple, orbital contents, and cheek drain to preauricular nodes.
• Lymph ultimately reaches deep cervical nodes.