Superior tarsal muscle

Last revised by Yoshi Yu on 21 Mar 2023

The superior tarsal muscle (Müller muscle or cremaster tarsus) is a small muscle of the superior orbit arising from the undersurface of the levator palpebrae superioris muscle that elevates and retracts the upper eyelid. It is not part of the extraocular muscles; it does not insert on the globe and therefore does not produce eye movements. It is composed of smooth muscle fibers which are under sympathetic control.


Clinical significance

  • Horner syndrome, due to injury or pathology of the cervical sympathetic chain, can lead to reduced sympathetic innervation of the muscle and cause ptosis. There are usually other signs of Horner syndrome present to help differentiate from other causes of ptosis.

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