Trigeminal Nerve (CN V)

00:01 Going back to cranial nerve V, the trigeminal nerve, has a lot of different nuclei all throughout the brainstem from the midbrain all the way down to the medulla.

00:15 And as the name implies, it's going to have three major components.

00:19 It's going to have an ophthalmic division, a maxillary division and a mandibular division.

00:25 The ophthalmic nerve is going to go along the lateral wall of the cavernous sinus through the superior orbital fissure and then give off several branches including the frontal nerve, the lacrimal nerve and the nasal ciliary nerve, all providing important sensory information.

00:44 The maxillary division or cranial nerve V2 is going to go through the wall of the cavernous sinus and then exit through the foramen rotundum before it passes over the pterygopalatine fossa and then give off some terminal branches.

01:04 It's actually going to travel all the way anteriorly through the inferior orbital fissure and then out the infraorbital foramen.

01:14 Where it will become the infraorbital nerve.

01:17 It's also going to give off many important branches including those to the upper teeth via superior alveolar nerves.

01:24 It's also going to give off some branches that go down towards the pterygopalatine area as well.

01:32 The third division, the mandibular branch is going to go through the foramen ovale and then through the infratemporal fossa and going to do something different from the other two branches of the trigeminal nerve.

01:47 It provides both sensory information and motor supply.

01:52 So it's going to give some sensory branches such as a auricolotemporal, or buccal nerve.

01:59 But then it's also going to innervate what are called the muscles of mastication, things like the temporalis and masseter.

02:05 Hence nerves like deep temporal or nerve to the masseter.

02:10 In terms of this sensory distribution, the ophthalmic is going to be responsible for part of the dermatome of the anterior part of the head down to the level of the eyes and the tip of the nose.

02:23 The maxillary division is going to come down in a strip that covers the cheek to the upper lips and then the lower portion is going to come down past the ears down to the jaw to cover the rest of the anterior aspect of the head.