Superior tarsal muscle

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
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	Raises the upper eyelid
Identifiers
Dorlands /Elsevier	m_22/12551061
TA
TH	{{#property:P1694}}
TE	{{#property:P1693}}
FMA	{{#property:P1402}}
Anatomical terms of muscle [[[d:|edit on Wikidata]]]

The superior tarsal 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. 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. The sympathetic fibres continue to the superior division of the oculomotor nerve, where they enter the superior tarsal muscle on its inferior aspect.

Actions

The superior tarsal muscle works to keep the upper eyelid raised after the levator palpebrae superioris has raised 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. The ptosis seen in Horner's syndrome is of a lesser degree than is seen with an oculomotor nerve palsy.

Etymology

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

Eponym

The term Müller's muscle is sometimes used as a synonym. However, the same term is also used for the circular fibres of the ciliary muscle, 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.

See also

Heinrich Müller (physiologist)