The short posterior ciliary arteries, around twenty in number, arise from the

medial posterior ciliary artery Medial may refer to: Mathematics * Medial magma, a mathematical identity in algebra Geometry * Medial axis, in geometry the set of all points having more than one closest point on an object's boundary * Medial graph, another graph that repr ...

and

lateral posterior ciliary artery Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction * Lateral cricoarytenoid muscle *Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral con ...

, which are 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 st ...

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 ...

Course and target

They pass forward around the

to the posterior part of the

eyeball Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conve ...

, pierce 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 human eye containing mainly collagen and some crucial elastic fiber. In humans, and som ...

around the entrance of the optic nerve, and supply the

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

(up to the equator of the eye) and

ciliary process Ciliary may refer to: * Cilium – projections from living cells that have locomotive or sensory functions * Ciliary body - the circumferential tissue inside the eye * Ciliary muscle - eye muscle used for focusing * Ciliary nerves (disambiguation ...

es. Some branches of the short posterior ciliary arteries also supply the

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 the ...

via 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

Arteries of the head and neck {{circulatory-stub

Course and target

Additional images

See also

References