Superior tarsal 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.)
Latin	musculus tarsalis superior
Origin	underside of levator palpebrae superioris
Insertion	superior tarsal plate of the eyelid
Artery	ophthalmic artery
Nerve	sympathetic nervous system
Actions	raise the upper eyelid

The superior tarsal muscle (also known as Müller's muscle) is a smooth muscle adjoining the levator palpebrae superioris muscle that helps to raise the upper eyelid.

Structure

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

Innervation

The superior tarsal muscle receives its innervation from the sympathetic nervous system on fibers carried along with the ophthalmic artery through the cavernous sinus. These postganglionic sympathetic fibers originate in the superior cervical ganglion.

Actions

The superior tarsal muscle works with the levator palpebrae superioris to raise the upper eyelid.

Pathology

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.

Etymology

from Ancient Greek ταρσός, a "flat surface" typically used for drying.

Eponym

The term "Müller's muscle" is sometimes used as a synonym.^[1]

However, the same term is also used for a portion of the ciliary muscle.^[2][3]

See also

Heinrich Müller (physiologist)

References

1. ^ van der Werf F, Baljet B, Prins M, Timmerman A, Otto JA (1993). "Innervation of the superior tarsal (Müller's) muscle in the cynomolgus monkey: a retrograde tracing study". Invest. Ophthalmol. Vis. Sci. 34 (7): 2333–40. PMID 7685010. http://www.iovs.org/cgi/pmidlookup?view=long&pmid=7685010. 
2. ^ doctor/2564 at Who Named It?
3. ^ "Glossary of Eponyms". http://www.dartmouth.edu/~humananatomy/resources/glossary.html. Retrieved 2008-02-23.