Superior tarsal muscle
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.


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


The superior tarsal muscle receives its innervation from the sympathetic nervous system on fibers carried along with the ophthalmic artery
Ophthalmic artery
The ophthalmic artery is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the OA supply all the structures in the orbit as well as some structures in the nose, face and meninges...

 through the cavernous sinus
Cavernous sinus
The cavernous sinus , within the human head, is a large collection of thin-walled veins creating a cavity bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.-Contents:...

. These postganglionic sympathetic fibers originate in the superior cervical ganglion
Superior cervical ganglion
The superior cervical ganglion , the largest of the cervical ganglia, is placed opposite the second and third cervical vertebræ. It contains neurons that supply sympathetic innervation to the face....



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


Damage to some elements of the sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...

 can inhibit this muscle, causing a drooping eyelid (partial ptosis
Ptosis (eyelid)
Ptosis is a drooping of the upper or lower eyelid. The drooping may be worse after being awake longer, when the individual's muscles are tired. This condition is sometimes called "lazy eye", but that term normally refers to amblyopia...

). This is seen in Horner's syndrome
Horner's syndrome
Horner's syndrome is the combination of drooping of the eyelid and constriction of the pupil , sometimes accompanied by decreased sweating of the face on the same side; redness of the conjunctiva of the eye is often also present...



The term "Müller's muscle" is sometimes used as a synonym.

However, the same term is also used for a portion of the ciliary muscle
Ciliary muscle
The ciliary muscle is a ring of striated smooth muscle in the eye's middle layer that controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humour into Schlemm's canal. It changes the shape of the lens within the eye not the size of the pupil which is...

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