Overview
The ophthalmic artery is typically the first major intracranial branch of the internal carotid artery. It arises just as the internal carotid artery emerges from the cavernous sinus. The ophthalmic artery has a rich anastomotic network the acts protectively against occlusion.
Origin
Ophthalmic C6 segment of the internal carotid artery
Course
The ophthalmic artery has an intracranial and extracranial course.
- It first emerges directly from the C6 segment of the internal carotid artery, medial to the anterior clinoid process of the sphenoid bone.
- It then courses intracranially before passing below the posterior edge of the falciform ligament
- It then pierces the dura mater of the optic nerve and enters the orbit via the optic canal, with and inferolateral to the optic nerve
- Within the optic canal, the ophthalmic artery travels inferolateral to the optic nerve
- The artery then crosses over (83%) or under (17%) the optic nerve from lateral to medial giving off its first branch
- After emerging from the optic canal, in the posterior third of the cone of the orbit, the artery turns sharply and medially to course anteriorly along the medial wall of the orbit, passing between the superior oblique and lateral rectus muscles
- Along its course, it gives off several branches before dividing into its terminal branches near the upper medial edge of the orbit.
Branches
- Central retinal artery
- Most critical and most commonly (78%) the first branch of the ophthalmic artery as it’s fundamental for vision.
- Supplies the optic nerve as well as the inner layers of the retina
- Lacrimal artery
- A large branch, arising just before the ophthalmic artery enters the orbit
- Supplies the lacrimal gland, eyelids, conjunctiva and parts of the dura mater
- Posterior ciliary arteries
- 1 to 5 long and short posterior ciliary arteries, pierce the sclera on the posterior aspect of the eyeball lateral to the optic nerve
- Supplies the choroid and outer layers of the retina
- Muscular branches
- Supplies the extraocular muscles, often via superior and inferior groups
- Accompanies the oculomotor nerve
- Gives off the anterior ciliary arteries
- Supraorbital artery
- Arises after the ophthalmic artery crosses over the optic nerve
- Exits the orbit with the supraorbital nerve and vein through the supraorbital foramen
- Intraorbitally supplies superior rectus and levator palpebrae superioris
- Extraorbitally supplies the skin, muscles and periosteum of the forehead
- Ethmoidal artery (anterior and posterior)
- Anterior is usually larger and originates more distally, it enters the cranial cavity through the anterior ethmoidal foramen on the medial orbital wall and becomes anterior meningeal artery, supplying ethmoidal air cells and the periosteum
- Posterior ethmoid artery supplies the superior oblique, superior and medial rectus and the levator palpebrae superioris
- In conjunction with the sphenopalatine artery, the anterior and posterior ethmoidal arteries form extensive anastomotic networks supplying the olfactory mucosa.
- Medial palpebral arteries (superior and inferior)
- Supplies the eyelids
- Terminal branches
- Supratrochlear artery, dorsal nasal artery
Supply
All structures of the orbit, upper two-thirds of the nose, nasal cavity, frontal area of the scalp, ethmoid and frontal sinuses, parts of meninges
Anatomical Variants
- Ophthalmic artery originating from the middle meningeal artery – first part of the maxillary artery
- Ophthalmic artery originating from anterior cerebral artery
- Ophthalmic artery enters the optic canal superior to the optic nerve
- Lacrimal artery originating from the middle meningeal artery
- Persistent dorsal ophthalmic artery
- Persistent ventral ophthalmic artery