Chapter contents Overview Somatic motor component Origin, central course Intracranial course Final innervation Visceral motor component Origin and course Final innervation

Cranial Nerve III - Oculomotor Nerve Page 5 of 16 Somatic motor component - origin and central course The somatic motor component of CN III originates from the oculomotor nucleus located in the rostral midbrain at the level of the superior colliculus. Like other somatic motor nuclei, the oculomotor nucleus is located near the midline just ventral to the cerebral aqueduct. In a coronal cross-section of the brainstem the oculomotor nucleus is "V-shaped" and is bordered medially by the Edinger-Westphal nucleus and laterally and inferiorly by the medial longitudinal fasciculus which allows communication between various brainstem nuclei. Figure 3-5. Somatic motor component - origin and central course.

		Fibers leaving the occulomotor nucleus travel ventrally in the tegmentum of the midbrain passing through the red nucleus and medial portion of the cerebral peduncle to emerge in the interpeduncular fossa at the junction of the midbrain and pons.

Last revised: March 22, 1998