The Ophthalmic Artery: Ii. Intra-Orbital Course

Abstract

MaterialTHIS study was carried out in 61 human orbits obtained from 38 dissectionroom cadavers. In 23 cadavers both the orbits were examined, and in the remaining fifteen only one side was studied. With the exception of three cadavers of children aged 4, 11, and 12 years, the specimens were from old persons.Method Neoprene latex was injected in situ, either through the internal carotid artery or through the most proximal part of the ophthalmic artery, after opening the skull and removing the brain. The artery was first irrigated with water. After injection the part was covered with cotton wool soaked in 10 per cent. formalin for from 24 to 48 hours to coagulate the latex. The roof of the orbit was then opened and the ophthalmic artery was carefully studied within the orbit. Observations COURSEFor descriptive purposes the intra-orbital course of the ophthalmic artery has been divided into three parts (Singh and Dass, 1960).(1) The first part extends from the point of entrance of the ophthalmic artery into the orbit to the point where the artery bends to become the second part. This part usually runs along the infero-lateral aspect of the optic nerve.(2) The second part crosses over or under the optic nerve running in a medial direction from the infero-lateral to the supero-medial aspect of the nerve.(3) The third part extends from the point at which the second part bends at the supero-medial aspect of the optic nerve to its termination. It lies medial to the nerve.In two places the ophthalmic artery bends to change direction: one is seen at the junction of the first and the second parts and is designated the "Angle" in the text (

Orbital vascular anatomy

“…3,4 However, in 26% of my specimens, the main part of the ophthalmic artery terminated at the level of the anterior ethmoid foramen by bifurcating into two trunks, one anterior ethmoid artery and the other a continuation of the ophthalmic artery to the superomedial angle of the orbital opening. 3 Branches of the ophthalmic artery I have described in detail the order and site of origin of the various branches of the ophthalmic artery and their supply.…”

“…Apart from occasional reports of various abnormalities, there had not been any systematic study on the ophthalmic artery till my detailed anatomical systematic studies in human beings. [2][3][4] I investigated its origin (in 170 specimens 2 ), intracranial and intracanalicular course (in 106 specimens 2 ), intraorbital course (in 61 specimens 3 ), and its branches (in 59 specimens 4 ). My studies revealed several discrepancies in Meyer's 1 description, particularly about branches, presumably because of small number (20) of specimens in his study.…”

“…2,3 The entire course of the ophthalmic artery can be divided into three parts: (a) intracranial, 2 (b) intracanalicular, 2 and (c) intraorbital. 3 …”

“…3 The intraorbital course can be divided into three parts (Figures 8, 10, and 11). The ophthalmic artery changes direction at two places: (i) at the junction of the first and second part, and (ii) between the second and third part.…”

Ophthalmic artery blood flow velocity changes in diabetic patients as a manifestation of macroangiopathy

“…The average diameter of the OA where it crosses the optic nerve is 1.33∫0.33 mm (Lang & Kageyama 1990). The branches of the OA are divided into 3 groups; the ocular group includes the central retinal and ciliary artery; the orbital group consists of the lacrimal and ocular muscular artery, and the extraorbital group including the posterior and anterior ethmoidal artery, supraorbital, supratrochlear and dorsal nasal arteries (Hayreh & Dass 1962). Arterio-and atherosclerotic changes in aged human orbital arteries have been studied in a few reports (Buchi et al 1993;Dyrka et al 1994;Eberle et al 1996).…”