CRANIAL NERVES IN RELATION TO THE BASE OF THE BRAIN
Cranial nerves are nerves that exit from the cranial cavity through openings in the cranium. There are 12 pairs of cranial nerves that are named and numbered in rostrocaudal sequence of their supercial origins from the brain, brainstem, and superior spinal cord. The olfactory nerves (CN I, not shown) end in the olfactory bulb. The entire origin of the spinal accessory nerve (CN XI) from the spinal cord is not included here; it extends inferiorly as far as the C6 spinal cord segment.
CRANIAL NERVES IN RELATION TO THE INTERNAL ASPECT OF THE CRANIAL BASE
The venous sinuses have been opened on the right side. The ophthalmic division of the trigeminal nerve (CN V1) and the trochlear (CN IV) and oculomotor (CN III) nerves have been dissected from the lateral wall of the cavernous sinus. Although there are no sympathetic bers in cranial nerves as they leave the brain, postsynaptic sympathetic nerve bers “hitch-hike” onto branches of cranial nerves having traveled to the region via major blood vessels.
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