The oculomotor nerve [III] leaves the anterior surface of the brainstem between the midbrain and the pons. It passes forward in the lateral wall of the cavernous sinus.
Just before entering the orbit the oculomotor nerve [III] divides into superior and inferior branches (Fig.
8.102). These branches enter the orbit through the superior orbital fissure, lying within the common tendinous ring (Fig. 8.101).