Sensory Innervation of the Face

Trigeminal Nerve: Structure and Function

The trigeminal nerve (cranial nerve V) is the primary sensory nerve of the face, responsible for transmitting sensory information from the skin, mucous membranes, and deeper structures.

Anatomy of the Trigeminal Nerve

The trigeminal nerve has three major divisions:

• Ophthalmic nerve (V1): Innervates the forehead, scalp, upper eyelid, and nose.
• Maxillary nerve (V2): Supplies sensation to the cheek, upper lip, and nasal mucosa.
• Mandibular nerve (V3): Innervates the lower lip, jaw, chin, and parts of the tongue.

Physiological Function

The trigeminal nerve carries sensory input related to touch, pain, and temperature from different regions of the face. Additionally, the mandibular division has motor functions responsible for mastication.

Clinical Significance

Damage or dysfunction of the trigeminal nerve can result in conditions such as:

• Trigeminal neuralgia: Characterized by severe, episodic pain in the areas supplied by the nerve.
• Herpes zoster ophthalmicus: A viral infection affecting the ophthalmic branch.
• Temporomandibular joint disorders (TMJ): Pain and dysfunction in the jaw.

Understanding the sensory pathways of the trigeminal nerve is crucial for diagnosing and managing neurological and dental conditions affecting facial sensation.