Anatomy of the trigeminal nerve

1. Big picture

The trigeminal nerve = cranial nerve V (CN V) is the main sensory nerve of the face and the motor nerve of mastication.

For the final exam, the examiner usually wants you to know:

• the three sensory divisions: V1 ophthalmic, V2 maxillary, V3 mandibular

• the four nuclei of CN V

• the jaw deviation rule

• the corneal reflex pathway

• the difference between peripheral trigeminal division loss and spinal trigeminal nucleus “onion-skin” loss

• how trigeminal anatomy helps localize brainstem lesions, especially lateral medullary/Wallenberg syndrome