Final answer:
The 6th cranial nerve exits the skull via the superior orbital fissure, located on the anterior wall of the middle cranial fossa.
Step-by-step explanation:
The 6th cranial nerve, also known as the abducens nerve, exits the skull via the superior orbital fissure. This large, irregular opening is located on the anterior wall of the middle cranial fossa, lateral to the optic canal, and under the projecting margin of the lesser wing of the sphenoid bone. The superior orbital fissure provides passage not only for the abducens nerve, which controls lateral eye movement, but also for other structures such as the ophthalmic veins, the oculomotor nerve (CN III), the trochlear nerve (CN IV), and the lacrimal, frontal, and nasociliary branches of the ophthalmic nerve (CN V1).