The ophthalmic artery arises medial to the anterior clinoid process as the ICA exits the cavernous sinus. It originates from the antero- or supero-medial surface of the ICA.
The ophthalmic artery passes into the orbit via the optic canal. It has numerous branches which are often grouped into those that supply the orbital content and those that supply the globe and related structures.
The two terminal branches of the ophthalmic artery are the supratrochlear and dorsal nasal arteries.
- lacrimal artery
- supraorbital artery
- posterior ethmoidal artery
- anterior ethmoidal artery
- internal palpebral artery
- supratrochlear artery (frontal artery)
- dorsal nasal artery
- central retinal artery: although rarely seen, the choroidal blush should be seen on all angiograms
- long posterior ciliary arteries
- short posterior ciliary arteries
- anterior ciliary artery
- muscular artery
A useful mnemonic to remember the branches of the ophthalmic artery is:
Embryologically, the orbit has dual supply from the supraorbital branch (which later becomes the middle meningeal artery) and from the ophthalmic artery but there can often be variation:
- communicating branch between the ophthalmic and middle meningeal artery is present; most frequently passes through the superior orbital fissure (up to 50%)
- when multiple branches are present (15%) then an additional small foramen (or multiple foramina) lateral to the superior orbital fissure are present (foramen of Hyrtl or the meningo-orbital foramen)
- the connecting branch is known as sphenoidal artery or recurrent meningeal artery or orbital branch of the middle meningeal branch
- meningo-ophthalmic artery: regression of proximal ophthalmic artery and entire orbit is supplied by the middle meningeal artery
These variants are important to recognize as embolization of a tumor supplied by the external carotid artery (e.g. meningioma or hemangiopericytoma) can result in blindness. This is reported as the most common variant origin and in this case, the ophthalmic artery enters the orbit via the superior orbital fissure or via its own canal.
Variations in origin or branching patterns may be common:
- middle meningeal artery can arise from the ophthalmic artery
- ophthalmic artery origin from the middle meningeal artery, middle cerebral artery or posterior communicating artery
- cavernous origin of the ophthalmic artery is less common