Ocular Anatomy: Blood Supply

superficial areas of the neck and head and a small portion to the ocular structures. Has 2 branches: facial and maxillary. Terminal branch is the superficial temporal artery.

Facial artery supplies the medial canthus through its terminal branch, the angular artery. It came from the external carotid, and becomes the angular.

Maxillary artery supplies the lower eyelid and lacrimal sac as it exits the orbit through the infraorbital foramen. It is a branch off of the external carotid just anterior to the ear, and initially enters the orbit through the inferior orbital fissure as the infraorbital artery. After it exits via the infraorbital foramen, it joins the angular and dorsonasal arteries.

Terminal branch of the external carotid. It has three branches that supply the superficial skin, muscles, and soft tissue around the face and orbit.

Enters skull through petrous portion of temporal bone, goes directly into the cavernous sinus. It traverses through the sinus with CNVI at its side and leaves the sinus with CNII medial and CN III lateral. As it approaches the orbit it gives off its first branch: the opthalmic artery

Enters the orbit within the optic nerve sheath. Leaves the sheath and courses along with the nasociliary nerve to the medial wall of the orbit. The ophthalmic artery is a branch of the internal carotid artery that has 7 branches.

1. Central retinal artery2. Lacrimal artery3. Short posterior ciliary arteries4. Long posterior ciliary arteries5. Ethmoid artery 6. Supraorbital artery7. Muscular artery

Runs within the optic nerve, nourishing the nerve and pia mater with its collateral branches. Enters the optic disc a little on the nasal side, then branches superiorly and inferiorly and then multiple times to supply the inner retina.

Runs along the border of the lateral rectus muscle, acting as its blood supply as it courses to the superior rectus and lacrimal gland, where it also provides innervation. Eventually, it becomes the lateral palpebral artery to supply the eyelids.

Pierces the back of the eye on both sides of the optic nerve as one or two branches: then quickly branches 10-20 times within the choiroidal stroma to form an arterial network, the circle of zinn, that supplies the superficial optic nerve head. they also supply the posterior choroid, including the macula.

The optic disc. It is made up of the short posterior ciliary arteries.

Two arteries that enter on each side of the optic nerve: like the short posterior ciliary arteries. They run between the sclera and choroid, where they join to form a network with the anterior choroid, and then traverse to the ciliary body to join with the anterior ciliary arteries to form the major arterial circle of the iris. overall, the long posterior ciliary arteries supply the iris, ciliary body, and anterior region of the choroid.

The major arterial circle of the iris has fenestrated capillaries. Plasma leaks out of the fenestrations and ultimately contributes to aqueous humor formation.

sphenoid, frontal, and ethmoid sinuses

provides for structures within the orbit (SR, SO, levator muscles) and also superficiallly, through the supraorbital notch to the forehead and scalp.