The Ciliary Arteries (aa. ciliares) are divisible into three groups, the long and short, posterior, and the anterior. The short posterior ciliary arteries from six to twelve in number, arise from the ophthalmic, or its branches; they pass forward around the optic nerve to the posterior part of the eyeball, pierce the sclera around the entrance of the nerve, and supply the choroid and ciliary processes. The long posterior ciliary arteries, two in number, pierce the posterior part of the sclera at some little distance from the optic nerve, and run forward, along either side of the eyeball, between the sclera and choroid, to the ciliary muscle, where they divide into two branches; these form an arterial circle, the circulus arteriosus major, around the circumference of the iris, from which numerous converging branches run, in the substance of the iris, to its pupillary margin, where they form a second arterial circle, the circulus arteriosus minor. The anterior ciliary arteries are derived from the muscular branches; they run to the front of the eyeball in company with the tendons of the Recti, form a vascular zone beneath the conjunctiva, and then pierce the sclera a short distance from the cornea and end in the circulus arteriosus major.
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