The short posterior ciliary arteries are a number of branches of the

ophthalmic artery The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some ...

. They pass forward with the optic nerve to reach the eyeball, piercing the

sclera The sclera, also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective outer layer of the eye containing mainly collagen and some crucial elastic fiber. In the development of t ...

around the entry of the optic nerve into the eyeball.

Anatomy

The number of short posterior ciliary arteries varies between individuals; one or more short posterior ciliary arteries initially branch off the ophthalmic artery, subsequently dividing to form up to 20 short posterior ciliary arteries.

Origin

The short posterior ciliary arteries branch off the

as it crosses the

optic nerve In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual system, visual information from the retina to the brain. In humans, the optic nerve i ...

medially.

Course and relations

About 7 short posterior ciliary arteries accompany the optic nerve, passing anterior-ward to reach the posterior part of the eyeball, where they divide into 15-20 branches and pierce the sclera around the entrance of the optic nerve.

Distribution

The short posterior ciliary arteries contribute arterial supply to the

choroid The choroid, also known as the choroidea or choroid coat, is a part of the uvea, the vascular layer of the eye. It contains connective tissues, and lies between the retina and the sclera. The human choroid is thickest at the far extreme rear o ...

ciliary process In the anatomy of the eye, the ciliary processes are formed by the inward folding of the various layers of the choroid, viz. the choroid proper and the lamina basalis, and are received between corresponding foldings of the suspensory ligame ...

es,

optic disc The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye. The ganglion cell axons form t ...

, the outer

retina The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...

, and

Bruch's membrane Bruch's membrane or lamina vitrea is the innermost layer of the choroid of the eye. It is also called the ''vitreous lamina'' or ''Membrane vitriae'', because of its glassy microscopic appearance. It is 2–4 μm thick. Anatomy Structure B ...

. Some branches of the short posterior ciliary arteries supply the

by means of an anastomotic ring - the circle of Zinn-Haller or ''circle of Zinn -'' which is associated with the fibrous extension of the ocular tendons (

common tendinous ring The common tendinous ring, also known as the annulus of Zinn or annular tendon, is a ring of fibrous tissue surrounding the optic nerve at its entrance at the apex of the orbit. It is the common origin of the four recti muscles of the group of ex ...

(also annulus of Zinn)).

Additional images

File:Gray880.png, The terminal portion of the optic nerve and its entrance into the eyeball, in horizontal section

References