Fig. 3 Orbital arterial supply derives from the internal carotid artery (InCA) by the first major intracranial branch, the ophthalmic artery (OA). The OA branches into the central retinal artery, muscular branches, posterior ciliary artery (PCA), posterior ethmoidal artery (PEA), anterior ethmoidal artery (AEA), and the lacrimal artery (LA) eventually terminating as the supratrochlear artery (STA) and supraorbital artery (SOA). (Courtesy of Deborah D. Sherman. MD, Nashville, TN)