Ciliary muscle

Ciliary muscle
The choroid and iris. (Ciliary muscle is labeled near top.)
Details
PronunciationUK: /ˈsɪliəri/, US: /ˈsɪliɛri/[2]
Origin1) longitudinal fibers → scleral spur; 2) circular fibers → encircle root of iris[1]
Insertion1) longitudinal fibers → ciliary process, 2) circular fibers → encircle root of iris[1]
ArteryLong posterior ciliary arteries
VeinVorticose veins
NerveShort ciliary
Parasympathetic fibers in the oculomotor nerve (CN-III) synapse in the ciliary ganglion. Parasympathetic postganglionic fibers from the ciliary ganglion travel through short ciliary nerves into the ocular globe.
Actions1) Accommodation, 2) regulation of trabecular meshwork pore sizes
Identifiers
Latinmusculus ciliaris
TA98A15.2.03.014
TA26770
FMA49151
Anatomical terms of muscle

The ciliary muscle is an intrinsic muscle of the eye formed as a ring of smooth muscle[3][4] in the eye's middle layer, the uvea (vascular layer). It controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humor into Schlemm's canal. It also changes the shape of the lens within the eye but not the size of the pupil[5] which is carried out by the sphincter pupillae muscle and dilator pupillae.

The ciliary muscle, pupillary sphincter muscle and pupillary dilator muscle sometimes are called intrinsic ocular muscles[6] or intraocular muscles.[7]

  1. ^ a b Gest, Thomas R; Burkel, William E. "Anatomy Tables - Eye." Medical Gross Anatomy. 2000. University of Michigan Medical School. January 5, 2010 Umich.edu Archived 2010-05-26 at the Wayback Machine
  2. ^ Wells, John C. (2008). Longman Pronunciation Dictionary (3rd ed.). Longman. ISBN 978-1-4058-8118-0.
  3. ^ Kleinmann, G; Kim, H. J.; Yee, R. W. (2006). "Scleral expansion procedure for the correction of presbyopia". International Ophthalmology Clinics. 46 (3): 1–12. doi:10.1097/00004397-200604630-00003. PMID 16929221. S2CID 45247729.
  4. ^ Schachar, Ronald A. (2012). "Anatomy and Physiology." (Chapter 4) The Mechanism of Accommodation and Presbyopia. Kugler Publications. ISBN 978-9-062-99233-1.
  5. ^ Land, Michael (Apr 19, 2015). "Focusing by shape change in the lens of the eye: a commentary on Young (1801) 'On the mechanism of the eye'". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 370 (1666). School of Life Sciences, University of Sussex, Brighton: Philosophical Transactions of the Royal Society B: Biological Sciences: 20140308. doi:10.1098/rstb.2014.0308. PMC 4360117. PMID 25750232.
  6. ^ Kels, Barry D.; Grzybowski, Andrzej; Grant-Kels, Jane M. (March 2015). "Human ocular anatomy". Clinics in Dermatology. 33 (2): 140–146. doi:10.1016/j.clindermatol.2014.10.006. PMID 25704934.
  7. ^ Ludwig, Parker E.; Aslam, Sanah; Czyz, Craig N. (2024). "Anatomy, Head and Neck: Eye Muscles". StatPearls. StatPearls Publishing. PMID 29262013.