E, The annular tendon has been divided in the interval between the origin of the superior and lateral rectus muscles. The oculomotor, abducens, and nasociliary nerves pass through the superior orbital fissure and annular tendon. The oculomotor nerve splits into superior and inferior divisions. The superior division branches on the lower surface of the superior rectus and sends branches along the medial margin of the superior rectus muscle to enter the levator muscle. The fibers of the inferior division give rise to three branches. One passes below the optic nerve to supply the medial rectus muscle, another enters the superior surface of the inferior rectus muscle, and the third branch courses along the lateral margin of the inferior rectus muscle to innervate the inferior oblique muscle. The branch to the inferior oblique muscle gives rise to the motor (parasympathetic) root to the ciliary ganglion. The nasociliary nerve arises from the medial surface of the ophthalmic nerve and gives rise to the sensory root of the ciliary ganglion. Short ciliary nerves arise from the ciliary ganglion and enter the globe around the optic nerve. The abducens nerve courses on the medial side of the ophthalmic nerve in the cavernous sinus, but it passes below the ophthalmic nerve in the superior orbital fissure to enter the medial surface of the lateral rectus muscle. F, A segment of the orbital portion of the optic nerve has been removed. This exposes the branch of the inferior division of the oculomotor nerve, which passes below the optic nerve and enters the medial rectus muscle. The short ciliary nerves arise from the ciliary ganglion and enter the globe around the margin of the optic nerve. (Images courtesy of AL Rhoton, Jr.)