Trigeminal (V) Nerve

The trigeminal nerve emerges from the anterolateral aspect of the upper pons. The large sensory root conveys sensation from most of the face and scalp; parts of the auricle; and the external acoustic meatus, the nasal, and oral cavities; teeth; temporomandibular joint; nasopharynx; and most of the meninges in the anterior and middle cranial fossae. It carries proprioceptive impulses from masticatory and, likely, from extraocular and facial muscles. The smaller medial motor root supplies muscles derived from the first branchial arch: the masticatory muscles, the mylohyoid, the anterior belly of the digastric, the tensor veli palatine, and tensor tympani. Numerous parasympathetic and sympathetic fibers join branches of the trigeminal nerve through interconnections with the oculomotor (III), trochlear (IV), facial (VII), and glossopharyngeal (IX) nerves. The sensory and motor roots emerge from the pons and travel over the superior border of the petrous temporal bone near its apex. The sensory root expands into the semilunar-shaped trigeminal ganglion (gasserian ganglion) and contains pseudounipolar cells with peripheral processes conveying sensory impulses from the face and head structures through the three major trigeminal divisions.

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