levator palpebrae superioris muscle
The levator palpebrae superioris muscle is a small muscle of the superior orbit 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 skeletal striated muscle fibers but on its undersurface, smooth muscle fibers form the superior tarsal muscle (Müller muscle), which is under sympathetic control.
Summary
- origin: inferior part of the lesser wing of the sphenoid bone in the posterior superior aspect of the orbit, just above the optic canal opening and tendinous ring
- insertion: superior tarsal plate and skin of the upper eyelid
- innervation: superior branch of the oculomotor nerve (CN III)
- action: elevates and retracts the upper eyelid
Related pathology
- oculomotor nerve palsy as a cause of ptosis
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