Parasagittal view of head through medial wall of orbit. The optic nerve and ophthalmic artery are seen entering the apex of the orbit. The superior oblique, medial rectus, inferior rectus, and inferior oblique muscles are also visible. The ophthalmic artery is a branch off the supraclinoid segment of the internal carotid artery. The cavernous segment of this artery is located along the lateral surface of the body of the sphenoid, which contains the sphenoid sinus as well as the sella turcica for the pituitary gland. The maxillary nerve courses along the lateral wall of the cavernous sinus before passing through foramen rotundum to enter the pterygopalatine fossa. Similarly, Vidian nerve passes into this fossa via Vidian canal and preganglionic parasympathetic fibers within this nerve synapse in the pterygopalatine ganglion. Postganglionic fibers are distributed along branches of the maxillary nerve. The largest branch of the maxillary nerve, the infraorbital nerve, enters the orbit via the inferior orbital fissure. It is shown coursing along the floor of the orbit to the face. Also shown entering the orbit is the zygomatic nerve. The floor of the orbit also serves as the roof of the maxillary sinus. The posterior wall of this sinus is related to the pterygopalatine fossa, which in turn is bounded posteriorly by the pterygoid process. (Image courtesy of AL Rhoton, Jr.)