Short ciliary nerves
Encyclopedia
The branches of the ciliary ganglion
are the short ciliary nerves.
These are delicate filaments, from six to ten in number, which arise from the forepart of the ganglion
in two bundles connected with its superior and inferior angles; the lower bundle is the larger.
They run forward with the ciliary arteries
in a wavy course, one set above and the other below the optic nerve
, and are accompanied by the long ciliary nerves
from the nasociliary.
They pierce the sclera
at the back part of the bulb of the eye, pass forward in delicate grooves on the inner surface of the sclera, and are distributed to the Ciliaris muscle, iris
, and cornea
.
The short ciliary nerve contains parasympathetic and sympathetic
nerve fibers. The parasympathetics arise from the Edinger-Westphal nucleus and synapse in the ciliary ganglion via the oculomotor nerve
, the postganglionic parasympathetics leave the ciliary ganglion in the short ciliary nerve and supply the ciliary body
and iris
. Sympathetics are provided by the superior cervical ganglion
and they reach the ganglion either as branches of the nasociliary nerve or directly from the extension of the plexus on the ophthalmic artery (sympathetic branch to ciliary ganglion).
Damage to the short ciliary nerve may result in loss of the pupillary light reflex, or mydriasis
.
Ciliary ganglion
The ciliary ganglion is a parasympathetic ganglion located in the posterior orbit. It measures 1–2 millimeters in diameter and contains approximately 2,500 neurons. Preganglionic axons from the Edinger-Westphal nucleus travel along the oculomotor nerve and form synapses with these cells...
are the short ciliary nerves.
These are delicate filaments, from six to ten in number, which arise from the forepart of the ganglion
Ganglion
In anatomy, a ganglion is a biological tissue mass, most commonly a mass of nerve cell bodies. Cells found in a ganglion are called ganglion cells, though this term is also sometimes used to refer specifically to retinal ganglion cells....
in two bundles connected with its superior and inferior angles; the lower bundle is the larger.
They run forward with the ciliary arteries
Ciliary arteries
The ciliary arteries are divisible into three groups, the long posterior, short posterior, and the anterior.* The short posterior ciliary arteries from six to twelve in number, arise from the ophthalmic as it crosses the optic nerve....
in a wavy course, one set above and the other below the optic nerve
Optic nerve
The optic nerve, also called cranial nerve 2, transmits visual information from the retina to the brain. Derived from the embryonic retinal ganglion cell, a diverticulum located in the diencephalon, the optic nerve doesn't regenerate after transection.-Anatomy:The optic nerve is the second of...
, and are accompanied by the long ciliary nerves
Long ciliary nerves
The long ciliary nerves, two or three in number, are given off from the nasociliary, as it crosses the optic nerve.They accompany the short ciliary nerves from the ciliary ganglion, pierce the posterior part of the sclera, and running forward between it and the choroid, are distributed to the iris...
from the nasociliary.
They pierce the sclera
Sclera
The sclera , also known as the white or white of the eye, is the opaque , fibrous, protective, outer layer of the eye containing collagen and elastic fiber. In the development of the embryo, the sclera is derived from the neural crest...
at the back part of the bulb of the eye, pass forward in delicate grooves on the inner surface of the sclera, and are distributed to the Ciliaris muscle, iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
, and cornea
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...
.
The short ciliary nerve contains parasympathetic and sympathetic
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
nerve fibers. The parasympathetics arise from the Edinger-Westphal nucleus and synapse in the ciliary ganglion via the oculomotor nerve
Oculomotor nerve
The oculomotor nerve is the 3rd of 12 paired cranial nerves. It enters the orbit via the superior orbital fissure and controls most of the eye's movements, including constriction of the pupil and maintaining an open eyelid by innervating the Levator palpebrae superiors muscle. The optic nerve is...
, the postganglionic parasympathetics leave the ciliary ganglion in the short ciliary nerve and supply the ciliary body
Ciliary body
The ciliary body is the circumferential tissue inside the eye composed of the ciliary muscle and ciliary processes. It is triangular in horizontal section and is coated by a double layer, the ciliary epithelium. This epithelium produces the aqueous humor. The inner layer is transparent and covers...
and iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
. Sympathetics are provided by the superior cervical ganglion
Superior cervical ganglion
The superior cervical ganglion , the largest of the cervical ganglia, is placed opposite the second and third cervical vertebræ. It contains neurons that supply sympathetic innervation to the face....
and they reach the ganglion either as branches of the nasociliary nerve or directly from the extension of the plexus on the ophthalmic artery (sympathetic branch to ciliary ganglion).
Damage to the short ciliary nerve may result in loss of the pupillary light reflex, or mydriasis
Mydriasis
Mydriasis is a dilation of the pupil due to disease, trauma or the use of drugs. Normally, the pupil dilates in the dark and constricts in the light to respectively improve vividity at night and to protect the retina from sunlight damage during the day...
.