Structure and Roots of the Ciliary Ganglion
- Ciliary ganglion is located just behind the eye in the posterior orbit and is 1-2 mm in diameter.
- Contains approximately 2,500 neurons in humans.
- Contains postganglionic parasympathetic neurons.
- Supplies the pupillary sphincter muscle and the ciliary muscle.
- Three types of axons enter the ciliary ganglion: sensory root, sympathetic root, and parasympathetic root.
- Sensory root branches from the nasociliary nerve and supplies the cornea, ciliary body, and iris.
- Sympathetic root originates from the internal carotid plexus and provides sympathetic supply to the blood vessels of the eye.
- Parasympathetic root branches from the inferior division of the oculomotor nerve and carries preganglionic parasympathetic axons from the Edinger-Westphal nucleus.
- Axons synapse onto postganglionic parasympathetic neurons within the ganglion.
- Short ciliary nerves exit from the anterior surface of the ciliary ganglion and contain sensory, postganglionic sympathetic, and postganglionic parasympathetic axons to the eye.

Clinical Significance and Diseases
- Diseases of the ciliary ganglion can produce a tonic pupil.
- Tonic pupil does not react to light and has an abnormally slow and prolonged response to attempted near vision.
- Adie syndrome is a common disease that affects the ciliary ganglion and causes tonic pupil plus absent deep tendon reflexes.
- Other diseases and conditions can denervate the ciliary ganglion and produce a tonic pupil.
- Trauma to the orbit can damage the short ciliary nerves.

Physiology and Tonic Pupil
- Tonic pupil explained by Irene Loewenfeld's theory.
- Ciliary ganglion contains more nerve fibers directed to the ciliary muscle than the pupillary sphincter muscle.
- Pathological destruction of nerve cells in the ciliary ganglion leads to aberrant nerve regeneration.
- Tonic constriction of the pupil with attempted near vision due to abnormal innervation of the ciliary muscle.
- Denervation supersensitivity causes the iris to become supersensitive to acetylcholine and constrict with weak cholinergic substances.

Light-near Dissociation
- Pupil does not react to light, but reacts to accommodation.
- Light-near dissociation occurs in some neurological disorders.
- Adie syndrome causes light-near dissociation and tonically dilated pupil.
- Brainstem damage can also cause light-near dissociation.
- Argyll Robertson pupil and Parinaud syndrome are brainstem causes of light-near dissociation.

Additional Information
- Plan of oculomotor nerve.
- Connections of the right sympathetic chain with thoracic, abdominal, and pelvic plexuses.
- Diagram of efferent sympathetic nervous system.
- Irene Loewenfeld is credited as the first physiologist to make the distinction of light-near dissociation.

References and External Links:
- Perez and Keyser (1986) conducted cell body counts in human ciliary ganglia.
- Kawasaki (1999) discussed physiology, assessment, and disorders of the pupil.
- Thompson and Kardon (2006) wrote about Irene E. Loewenfeld, a physiologist of the pupil.
- Thompson (1977) made new observations on Adie syndrome.
- Various references with relevant information on the topic.
- Anatomy figure: 29:03-04 at Human Anatomy Online, SUNY Downstate Medical Center - A deeper dissection of the right orbit from a superior approach.

Ciliary ganglion (Wikipedia)

The ciliary ganglion is a bundle of nerves, parasympathetic ganglion located just behind the eye in the posterior orbit. It is 1–2 mm in diameter and in humans contains approximately 2,500 neurons. The ganglion contains postganglionic parasympathetic neurons. These neurons supply the pupillary sphincter muscle, which constricts the pupil, and the ciliary muscle which contracts to make the lens more convex. Both of these muscles are involuntary since they are controlled by the parasympathetic division of the autonomic nervous system.

Ciliary ganglion
Detailed view of nerves of lateral orbit showing the ciliary ganglion immediately behind the globe of the eye.
Details
From	sensory root of ciliary ganglion sympathetic root of ciliary ganglion parasympathetic root of ciliary ganglion
To	short ciliary nerves
Identifiers
Latin	ganglion ciliare
TA98	A14.3.02.003
TA2	6663
FMA	6964
Anatomical terms of neuroanatomy [edit on Wikidata]

The ciliary ganglion is one of four parasympathetic ganglia of the head. The others are the submandibular ganglion, pterygopalatine ganglion, and otic ganglion.