Neuroanatomy, Cranial Nerve 5 (Trigeminal)

The trigeminal nerve is the 5th cranial nerve (CN V) and the largest of the cranial nerves (see . Cranial Nerves in the Orbit). CN V provides most of the face's sensory innervation and the mastication muscles' motor stimulation. The nerve's 3 main branches are the ophthalmic (V1), maxillary (V2), and mandibular (V3) nerves. These branches join at the trigeminal ganglia within the Meckel cave in the middle cranial fossa. Trigeminal nerve dysfunction can result in painful conditions like trigeminal neuralgia and difficulties with chewing and facial movements. These conditions can significantly impact a person's quality of life and require careful diagnosis and management by healthcare professionals. Surgical procedures that risk CN V injury include maxillofacial tumor removal, facial fracture repair, microvascular decompression, endoscopic sinus surgery, and mastoidectomy. A profound understanding of trigeminal nerve anatomy guides diagnosis, treatment planning, patient education, and complication prevention.