The levator palpebrae superioris ( la, elevating muscle of upper eyelid) is the

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of mus ...

in the

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...

that elevates the upper eyelid.

Structure

The levator palpebrae superioris originates from inferior surface of the lesser wing of the

sphenoid bone The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the o ...

, just above the optic foramen. It broadens and decreases in thickness (becomes thinner) and becomes the levator aponeurosis. This portion inserts on the skin of the upper eyelid, as well as the superior

tarsal plate The tarsi (tarsal plates) are two comparatively thick, elongated plates of dense connective tissue, about in length for the upper eyelid and 5 mm for the lower eyelid; one is found in each eyelid, and contributes to its form and support. They ...

. It is a

skeletal muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of m ...

. The

superior tarsal muscle 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 inser ...

, a smooth muscle, is attached to the levator palpebrae superioris, and inserts on the superior tarsal plate as well.

Blood supply

The levator palebrae superioris receives its blood supply from branches of the

ophthalmic artery The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some s ...

, specifically, muscular branches and the supraorbital artery. Blood is drained into the superior ophthalmic vein.

Nerve supply

The levator palpebrae superioris receives motor innervation from the superior division of the

oculomotor nerve The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements of ...

. The smooth muscle that originates from its undersurface, called the

is innervated by postganglionic sympathetic axons from the superior cervical ganglion.

Function

The levator palpebrae superioris elevates the upper eyelid.

Clinical significance

Damage to this muscle or its innervation can cause ptosis, which is drooping of the eyelid. Lesions in CN III can cause ptosis, because without stimulation from the oculomotor nerve the levator palpebrae cannot oppose the force of gravity, and the eyelid droops. Ptosis can also result from damage to the adjoining

or its sympathetic innervation. Such damage to the sympathetic supply occurs in

Horner's syndrome Horner's syndrome, also known as oculosympathetic paresis, is a combination of symptoms that arises when a group of nerves known as the sympathetic trunk is damaged. The signs and symptoms occur on the same side (ipsilateral) as it is a lesion ...

and presents as a partial ptosis. It is important to distinguish between these two very different causes of ptosis. This can usually be done clinically without issue, as each type of ptosis is accompanied by other distinct clinical findings. The ptosis seen in paralysis of the levator palpebrae superioris is usually more pronounced than that seen due to paralysis of the superior tarsal muscle.

Additional images

File:Gray893.png, Sagittal section through the upper eyelid. File:Trochlear and frontal nerves.jpg, Levator palpebrae superioris muscle File:Slide16aa.JPG, Levator palpebrae superioris muscle File:Slide1abaa.JPG, Extrinsic eye muscle. Nerves of orbita. Deep dissection. File:Slide3abab.JPG, Extrinsic eye muscle. Nerves of orbita. Deep dissection.

References

External links

* * () {{Authority control Muscles of the head and neck Human eye anatomy