Oculomotor nerve (Latin)

The n. oculomotorius (CN III) arises from the complexus oculomotorius which is located in the midbrain (mesencephalon), ventral to the substantia grisea periaquaeductalis, at the level of the colliculus superior. It is comprised of two nuclei: the ncl. nervi oculomotorii (contains cell bodies of general somatic efferent (GSE, motor) neurons), and the ncl. accessorius nervi oculomotorii (of Edinger-Westphal, contains cell bodies of general visceral efferent (GVE, parasympathetic) neurons). Efferent fibres emerge from the midbrain into the fossa/cisterna interpeduncularis as the n. oculomotorius, which continues through the lateral wall of the sinus cavernosus. From here, it enters the orbit the fissura orbitalis superior (internal to the anulus tendineus communis) as two branches which innervate the majority of the extraocular muscles:R. superior: m. rectus superior and mm. levator palpebrae superioris. R. inferior: m. rectus medialis, m. rectus inferior and m. obliquus inferior.The r. inferior also carries preganglionic parasympathetic fibers which synapse with postganglionic neurons in the ganglion ciliaris; these fibers provide parasympathetic innervation to the m. ciliaris and m. sphincter pupillae responsible for accommodation and pupillary constriction, via the nn. ciliares breves.