Vessels of the orbit

 Ophthalmic Artery

Origin

The ophthalmic artery is a branch of the cerebral part of the internal carotid artery, given off medial to the anterior clinoid process close to the optic canal

Course and Relations

1. The artery enters the orbit through the optic canal, lying inferolateral to the optic nerve. 

Both the artery and nerve lie in a common dural sheath.

2. In the orbit, the artery pierces the dura mater, ascends over the lateral side of the optic nerve, and 

crosses above the nerve from lateral to medial side along with the nasociliary nerve. 

It then runs forwards along the medial wall of the orbit between the superior oblique and the medial rectus muscles, and parallel to the nasociliary nerve.

3. It terminates near the medial angle of the eye by dividing into the supratrochlear and dorsal nasal branches

Branches

While still within the dural sheath, the ophthalmic artery gives off the central artery of the retina. 

After piercing the dura mater, it gives off a large lacrimal branch that runs along the lateral wall of the orbit. 

The main artery runs towards the medial wall of the orbit giving off a number of branches.

The central artery of retina is the first and most important branch of the ophthalmic artery. 

It first lies below the optic nerve. 

It pierces the dural sheath of the nerve and runs forwards for a short distance between these two. 

It then enters the substance of the nerve and runs forwards in its centre to reach the optic disc 

Here it divides into branches that supply the retina

The central artery of the retina is an end artery.

It does not have effective anastomoses with other arteries.

Occlusion of the artery results in blindness. 

The intraocular part of the artery can be seen, in the living, through an ophthalmoscope.

Branches from Lacrimal artery

1. Branches are given to the lacrimal gland.

2. Two zygomatic branches enter canals in the zygomatic bone. One branch appears on the face

through the zygomaticofacial foramen. The other appears on the temporal surface of the bone 

through the zygomaticotemporal foramen.

3. Lateral palpebral branches supply the eyelids.

4 A recurrent meningeal branch runs backwards to enter the middle cranial fossa through the superior orbital fissure.

5. Muscular branches supply the muscles of the orbit.

1. The posterior (long and short) ciliary arteries supply chiefly the choroid and iris. 

The eyeball is also supplied through anterior ciliary branches which are given off from arteries supplying 

muscles attached to the eyeball.

2. The supraorbital and supratrochlear branches supply the skin of the forehead.

3. The anterior and posterior ethmoidal branches enter foramina in the medial wall of the orbit to supply the ethmoidal air sinuses. 

They then enter the anterior cranial fossa. 

The terminal branches of the anterior artery enter the nose and supply part of it.

4. The medial palpebral branches supply the eyelids.

5. The dorsal nasal branch supplies the upper part of the nose.

Clinical Anatomy

The anterior ciliary arteries arise from the muscular branches of ophthalmic artery. 

The muscular arteries are important in this respect.

The central artery of retina is the only arterial supply to most of the nervous layer, the retina of the eye. If this artery is blocked, there is sudden blindness.

Ophthalmic Veins

The superior ophthalmic vein: 

• It accompanies the ophthalmic artery. 
• It lies above the optic nerve. 
• It receives tributaries corresponding to the branches of the artery, 
• passes through the superior orbital fissure, and drains into the cavernous sinus. 
• It communicates anteriorly with the supraorbital and angular veins

The Inferior ophthalmic vein: 

It runs below the optic nerve.

It receives tributaries from the lacrimal sac, the lower orbital muscles, and the eyelids, and 

ends either by joining the superior ophthalmic vein or drains directly into the cavernous sinus. 

It communicates with the pterygoid plexus of veins by small veins passing through the inferior orbital fissure.

Watch the lectures on YouTube:

Blood vessels of the Orbit | Ophthalmic artery & branches | Superior & Inferior Ophthalmic Veins