Orbital vascular anatomy

Abstract

The anatomy of the orbital vascular bed is highly complex, with tremendous interindividual variations. The main source of blood supply to the orbit is by the ophthalmic artery, the first branch of the internal carotid artery. The origin, course, and branches of the ophthalmic artery, and the genesis of the variations in origin, course, and branching pattern of the ophthalmic artery are discussed. The external carotid artery normally contributes only to a small extent to the orbital blood supply via the infraorbital artery and orbital branch of the middle meningeal artery. The complex, highly variable and confusing orbital venous system can be divided into: (i) main orbital veins (superior and inferior ophthalmic veins), (ii) inconstant orbital veins (middle and medial ophthalmic veins and four collateral veins), (iii) orbital venous networks, and (iv) various venous tributaries. All these are described briefly.

Intra-Arterial Chemotherapy as a Treatment for Intraocular Retinoblastoma: Alternatives to Direct Ophthalmic Artery Catheterization

“…When this orbital branch is developed enough to be catheterized, contrast or chemotherapy drugs can be injected to fill the lacrimal artery and reflux into the OA, resulting in flow of chemotherapy to the eye through the normal ciliary and retinal circulation. Additionally, the most prevalent (but rare) alternative origin of the OA, reported as early as 1887, is from the MMA, 8,17 which can be another alternative anatomic route for delivery of intra-arterial chemotherapy to the eye.…”

“…In young children, the OA is sometimes too small for catheterization by the usual microcatheters. Anatomic variations are common within the orbit, and rarely, the primary blood supply to the globe comes from another artery, most often the MMA, 8 making it impossible to catheterize with the standard direct OA technique. The angle of the OA take off from the ICA can also make catheterization difficult.…”

Dangerous Extracranial–Intracranial Anastomoses and Supply to the Cranial Nerves: Vessels the Neurointerventionalist Needs to Know

“…7,14,15 The sphenopalatine artery, also from the distal IMA, is connected with the anterior and posterior ethmoidal arteries of the ophthalmic artery through the septal arteries, which are classically seen in large juvenile angiofibromas. 16 The sphenopalatine artery is one of the targets in the embolization of epistaxis; therefore, these anastomoses have to be kept in mind.…”

Retinal Artery Embolization During Carotid Angioplasty and Carotid Artery Stenting -Case Report-

“…4,7) Anastomoses are located between the recurrent branch of the lacrimal artery and the orbital branch of the MMA. Variations can be classified by origin, intraorbital course of the ophthalmic artery, and contribution of the MMA.…”