Anatomy

Origin

It is a ring of smooth muscle.It is part of the vascular layer (middle layer) of the eyeball, it is adherent to the ciliary body, from it some fibers end up on the capsule of the crystalline lens.

Nerve

The ciliary muscle receives parasympathetic fibers from the short ciliary nerves that arise from the ciliary ganglion.  The parasympathetic postganglionic fibers are part of cranial nerve V (Nasociliary nerve of the trigeminal), while presynaptic parasympathetic fibers to the ciliary ganglia are from the oculomotor nerve. The postganglionic sympathetic innervation arises from the superior cervical ganglia.