Superior tarsal muscle

The superior tarsal muscle is a smooth muscle adjoining the levator palpebrae superioris muscle that helps to raise the upper eyelid.

Not to be confused with the orbitalis muscle or the circular fibres of the ciliary muscle, both of which are also known as Müller's muscle.
Superior tarsal muscle
The tarsi and their ligaments. Right eye; front view (muscle not labeled but region is visible).
Sagittal section of right orbital cavity (muscle not labeled but region is visible).
Details
OriginUnderside of levator palpebrae superioris
InsertionSuperior tarsal plate of the eyelid
ArteryOphthalmic artery
NerveSympathetic nervous system
ActionsRaises the upper eyelid
Identifiers
LatinMusculus tarsalis superior
TAA15.2.07.045
FMA49058
Anatomical terms of muscle

Structure

The superior tarsal muscle originates on the underside of levator palpebrae superioris and inserts on the superior tarsal plate of the eyelid.

Nerve supply

The superior tarsal muscle receives its innervation from the sympathetic nervous system. Postganglionic sympathetic fibers originate in the superior cervical ganglion, and travel via the internal carotid plexus, where small branches communicate with the oculomotor nerve as it passes through the cavernous sinus.[1] The sympathetic fibres continue to the superior division of the oculomotor nerve, where they enter the superior tarsal muscle on its inferior aspect.

Function

The superior tarsal muscle works to keep the upper eyelid raised after the levator palpebrae superioris has raised the upper eyelid.

Clinical significance

Damage to some elements of the sympathetic nervous system can inhibit this muscle, causing a drooping eyelid (partial ptosis). This is seen in Horner's syndrome. The ptosis seen in Horner's syndrome is of a lesser degree than is seen with an oculomotor nerve palsy.

History

The muscle derives its name from Greek ταρσός, meaning 'flat surface', typically used for drying.

The term Müller's muscle is sometimes used as a synonym.[2] However, the same term is also used for the circular fibres of the ciliary muscle,[3][4] and also for the orbitalis muscle that covers the inferior orbital fissure. Given the possible confusion, the use of the term Müller's muscle should be discouraged unless the context removes any ambiguity.

gollark: You insisted you were right, weren't really up to debating in good faith about it, launched a nonsensical vote, and ignored all criticism.
gollark: What I am saying (part of it) is that *regardless* of whether you think changing the rules like this is a good idea - I don't, gibson might, palaiologogoasgaosfiaosd does - the way this whole thing has been handled has been awful.
gollark: Thus, bee you.
gollark: Which you did by cancelling it and others like it.
gollark: Learning one language is easier than two.

See also

Heinrich Müller (physiologist)

References
  1. Snell R, Lemp M (1998). Clinical Anatomy of the Eye (2nd ed.). Oxford, UK: Blackwell Publishing. ISBN 9780632043446.
  2. van der Werf F, Baljet B, Prins M, Timmerman A, Otto JA (June 1993). "Innervation of the superior tarsal (Müller's) muscle in the cynomolgus monkey: a retrograde tracing study". Investigative Ophthalmology & Visual Science. 34 (7): 2333–40. PMID 7685010.
  3. doctor/2564 at Who Named It?
  4. "Glossary of Eponyms". Retrieved 2008-02-23.

Further reading
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.