ABSTRACT
Objective To study the anatomical features and operative significance of ophthalmic segment of internal carotid artery by the lateral orbital keyhole approach .Methods Selected 15 cases (30 sides) adult cadavers with formalin perfusion including 2 fresh cadavers perfused with red and blue latex and simulated by lateral orbital keyhole craniotomy .Surgical microscope was used to observe the morphologi-cal characteristics ,adjacent relaionship and important perforating vessels of the ophthalmic artery segment of internal carotid artery .The data measured after the brain was removed from the brain .Results The ophthalmic segment of internal carotid artery originated from the distal dura ring of upper cavernous sinus sphenoidalis and ended at the initial side of posterior communicating artery .The anterior half segment was blocked by the anterior process and the optic nerve and sent out fibrous structures to wrap the surrounding tissue .The starting point of oph-thalmic artery located at 5 mm of anterior end of the anterior process in 28 sides (82.4％),5 mm of the medial aspect of the anterior process in 22 sides (64.7％).The superior hypophyseal artery (SHA) could send 2 to 3 grades of perforating vessels to supply the anterior optic nerve,optic chiasma and pituitary stalk .Conclusion When we treat sellar region lesions by the lateral orbital keyhole approach ,especially for clipping the aneurysm at the ophthalmic segment ,we should expertly master the anatomical features of ophthalmic segment of internal ca -rotid artery,focus on protecting these perforating vessels ,and it has important clinical significance for the prognosis of the patients .