Superior view of the right orbit. The orbital plate of the frontal bone and periorbita have been removed to reveal the contents of the orbit. The eyeball or globe occupies the anterior half of the orbit while the extraocular muscles, fat, and neurovascular elements populate the posterior half. The latter structures enter the apex of the orbit through the optic canal (for the optic nerve and ophthalmic artery) and the superior orbital fissure (for the oculomotor, trochlear, ophthalmic, and abducens nerves, and the superior ophthalmic vein). The optic nerve, developmentally a tract of the brain, is enclosed by meninges as the optic nerve sheath. Just prior to their entrance at the superior orbital fissure the nerves within the lateral wall of the cavernous sinus are arranged in a superior to inferior order: oculomotor, trochlear, and ophthalmic. Several superficial orbital structures can be seen in this perspective: The lacrimal nerve, a branch of the ophthalmic nerve, courses along the lateral wall of the orbit in company with the lacrimal artery, a branch of the ophthalmic artery. They follow along the superior border of the lateral rectus muscle to the lacrimal gland. The frontal nerve, a branch of the ophthalmic nerve, courses forward in the orbit superficial to the levator palpebrae superioris and superior rectus muscles. It subsequently divides into the supraorbital (the larger of the two) and supratrochlear branches. The supraorbital artery follows the supraorbital nerve to the supraorbital notch or foramen. The trochlear nerve enters the orbit medial to the frontal nerve and bends medialward to enter the superior border of the superior oblique muscle. The major contents of the orbit are drained by the superior ophthalmic vein which passes posteriorly through the superior orbital fissure to the cavernous sinus. The medial wall of the orbit borders the lateral walls of the ethmoid and sphenoid sinuses. (Image courtesy of AL Rhoton, Jr.)