The oculomotor nerve originates from two nuclei in the brainstem - the motor somatomotor nucleus and the visceral motor Edinger-Westphal nucleus. It exits the brainstem and passes through the dura mater and cavernous sinus before entering the orbit through the superior orbital fissure. Within the orbit, the oculomotor nerve divides into superior and inferior divisions, with the superior division supplying the levator palpebrae superioris and superior rectus muscles, and the inferior division supplying the medial rectus, inferior rectus, and inferior oblique muscles.

1. Oculomotor Nerve
The third Nerve
Nuclei: Nerve originates from
two nuclei
1.Motor neurons in the oculomotor
(somatomotor)
2.Edinger-Westphal (visceral
motor) nuclei in the brainstem
Axons emerge out of nucleus , exit
the ventral surface of the
brainstem as the oculomotor nerve
passes through the dura mater,
lateral wall of the cavernous sinus
and then enters the superior orbital
fissure to access the orbit.
Somatomotor component of the
nerve divides into a superior and
inferior division

2. The superior
division supplies
levator palpebra
superioris and
superior rectus
muscles
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The inferior division supplies medial rectus, inferior rectus and inferior oblique muscles.
The visceromotor or parasympathetic component of the oculomotor nerve travels with inferior
division. In the orbit the inferior division sends branches that enter the ciliary ganglion where
they form functional contacts (synapses) with the ganglion cells