Ciliary ganglion

Ciliary ganglion
Detailed view of nerves of lateral orbit showing the ciliary ganglion immediately behind the globe of the eye.
Details
From	nasociliary nerve
To	Parasympathetic root of ciliary ganglion, Sympathetic root of ciliary ganglion, Sensory root of ciliary ganglion
Identifiers
Latin	ganglion ciliare
Dorlands /Elsevier	g_02/12384404
TA	A14.3.02.003
FMA	6964
Anatomical terms of neuroanatomy []

The ciliary ganglion is a parasympathetic ganglion located just behind the eye in the posterior orbit. It measures 1–2 millimeters in diameter and in humans contains approximately 2,500 neurons. The oculomotor nerve coming into the ganglion contains preganglionic axons from the Edinger-Westphal nucleus (a part of the brainstem) which form synapses with the ciliary neurons. The postganglionic axons run in the short ciliary nerves and innervate two eye muscles:

Both of these muscles are involuntary – they are controlled by the autonomic nervous system.

It is one of four parasympathetic ganglia of the head and neck. (The others are the submandibular ganglion, pterygopalatine ganglion, and otic ganglion).

Three types of nerve fibers run through the ciliary ganglion: parasympathetic fibers, sympathetic fibers and sensory fibers. Only parasympathetic fibers form synapses in the ganglion. The other two types of nerve fibers simply pass through. In classical anatomy, the ciliary ganglion is said to have three “roots:”

Diseases of the ciliary ganglion produce a tonic pupil. This is a pupil that does not react to light (it is “fixed”) and has an abnormally slow and prolonged response to attempted near vision (accommodation).

When a patient with an Adie pupil attempts to focus on a nearby object, the pupil (which would normally constrict rapidly) constricts slowly. On close inspection, the constricted pupil is not perfectly round. When the patient focuses on a more distant object (say the far side of the room), the pupil (which would normally dilate immediately) remains constricted for several minutes, and then slowly dilates back to the expected size.