Trigeminal nerve 5th cranial nerve (CN5) Largest cranial nerve MIXED CRANIAL NERVE Sensory to face – 3 dermatomes Motor to muscles of mastication The trigeminal nerve exits from the anterolateral surface of the pons as a large sensory root and a small motor root. These roots continue forward out of the posterior cranial fossa and into the middle cranial fossa by passing over the medial tip of the petrous part of the temporal bone . In the middle cranial fossa the sensory root expands into the trigeminal ganglion, which contains cell bodies for the sensory neurons in the trigeminal nerve and is comparable to a spinal ganglion. The ganglion is in a depression (the trigeminal depression) on the anterior surface of the petrous part of the temporal bone, in a dural cave (the trigeminal cave ). The motor root is below and completely separate from the sensory root at this point. Arising from the anterior border of the trigeminal ganglion are the three terminal divisions of the trigeminal nerve, which in descending order are: The ophthalmic nerve V1 The maxillary nerve V2 The mandibular nerve V3

2. • 5th cranial nerve (CN5)
• Largest cranial nerve
• MIXED CRANIAL NERVE
• Sensory to face – 3 dermatomes
• Motor to muscles of mastication

5. Branches
1. Meningeal branch :- to close related structures
2. Frontal nerve :- enters orbit above the common
tendinous ring then divides into supra-orbital and
supratrochlear nerves
3. Lacrimal branch :- receive parasympathetic
fibers from the great petrosal nerve of CN VII
through the zygomatic branch of CN V2
4. Nasociliary nerve :- then divided to
( 6 ) branches