Learning Objective: After completing this section, learners should be able to describe the anatomical course of the maxillary nerve (CN V2), identify the sensory distribution of its branches, explain its parasympathetic connections, and understand its clinical significance, including conditions such as trigeminal neuralgia.

Maxillary Nerve (CN V2)

The maxillary nerve is the second branch of the trigeminal nerve, developing from the first pharyngeal arch. Its primary function is sensory innervation to the mid-third of the face, including the lower eyelid, cheeks, lateral nose, upper lip, upper teeth, maxillary sinus, superior palate, and posterior inferior nasal cavity.

Anatomical Course

The trigeminal nerve arises from four brainstem nuclei (midbrain to medulla):

• Three sensory nuclei: mesencephalic, principal sensory, and spinal
• Motor nucleus: gives fibers to the mandibular nerve (V3)

The sensory root forms the trigeminal ganglion in the middle cranial fossa, lateral to the cavernous sinus, in a depression called Meckel’s cave. From the trigeminal ganglion, three terminal branches arise:

• Ophthalmic nerve (V1)
• Maxillary nerve (V2)
• Mandibular nerve (V3)

The maxillary nerve passes through the lateral wall of the cavernous sinus, exits the skull via the foramen rotundum, and gives off the following sensory branches:

• Superior alveolar nerves (anterior, middle, posterior)
• Middle meningeal nerve
• Infraorbital nerve
• Zygomatic nerve
• Inferior palpebral nerve
• Superior labial nerve
• Pharyngeal nerve
• Greater and lesser palatine nerves
• Nasopalatine nerve

Sensory Function

The terminal branches of the maxillary nerve innervate:

• Lower eyelid and conjunctiva
• Cheeks
• Lateral nose
• Upper lip, teeth, and gingiva
• Maxillary sinus
• Superior palate
• Posterior inferior portion of the nasal cavity

Parasympathetic Function

Postganglionic fibers from the pterygopalatine ganglion (facial nerve origin) travel with branches of V2 to supply:

• Lacrimal gland (via zygomatic and lacrimal nerves)
• Mucous glands of the nasal cavity and palate

Clinical Relevance: Trigeminal Neuralgia

Trigeminal neuralgia is a neuropathic pain disorder affecting the trigeminal nerve distribution, most often involving the maxillary (V2) or mandibular (V3) branches. Features include:

• Hyperalgesia – increased sensitivity to pain
• Allodynia – pain from normally non-painful stimuli

Light touch can trigger excruciating, stabbing facial pain. Causes may include nerve compression, multiple sclerosis, stroke, or trauma. First-line management is carbamazepine, which reduces nerve excitability; refractory cases may require surgical intervention, which can cause sensory loss.