Nucleus nervi oculomotorii
Last edit by Alaric Steinmetz on
Synonyms: Ncl. n. oculomotorii, oculomotor nucleus
The Nucleus nervi oculomotorii is a somatomotor nuclear complex of the Nervus oculomotorius.
Function
The efferent fibers run in the oculomotor nerve and innervate the levator palpebrae superioris muscle and all extraocular muscles, with the exception of the superior oblique and lateral rectus muscles.
Anatomy
The Nucleus nervi oculomotorii is located paramedian, slightly anterior to the Aqueduct, at the level of the Colliculi superiores in the tegmentum of the Midbrain. Each muscle innervated by the oculomotor nerve corresponds to its own subdivision within the Nucleus nervi oculomotorii. The nuclear region for the levator palpebrae muscle is not paired, as is otherwise the case with all cranial nerve nuclei, but is unpaired in the midline between the right and left Nucleus nervi oculomotorii. Thus, there is only one nucleus supplying both levator muscles[^1].
Schematic illustration
Clinical manifestations of lesions
A lesion of the Nucleus nervi oculomotorii results in paralysis of most of the extraocular muscles. Only the lateral rectus muscle and the superior oblique muscle remain functional, resulting in lateral and downward deviation of the eye on the affected side, which causes diplopia. In addition, Ptosis occurs due to paralysis of the levator palpebrae superioris muscle. The symptoms described often occur bilaterally because the oculomotor nuclear complexes on both sides are so close together that they can easily be damaged simultaneously.
