The
trigeminal nerve (the
fifth cranial nerve, or simply CN
V) is a
nerve responsible for sensation in the face and motor functions such as biting and chewing. The largest of the
cranial nerves, its name ("trigeminal" =
tri-, or three and
-geminus, or twin; thrice-twinned) derives from the fact that each trigeminal nerve (one on each side of the
pons) has three major branches: the
ophthalmic nerve (V
1), the
maxillary nerve (V
2), and the
mandibular nerve (V
3). The ophthalmic and maxillary nerves are purely sensory, and the mandibular nerve has sensory (or "cutaneous") and motor functions.