The ganglion occupies the back of the orbit between the lateral rectus muscle and the optic nerve. It lies in front of the ophthalmic artery.
The sensory or long root is derived from the nasal (naso-ciliary) branch of the ophthalmic, the motor or short root from the inferior division of the oculo-motor, and the sympathetic root from the plexus around the internal carotid artery.
Twelve to fourteen short ciliary nerves which accompany the optic nerve to the eyeball. They innervate the ciliary muscle and the iris.
The circular fibres of the iris are supplied by the oculomotor nerve, and the radial fibres by the sympathetic.