Levator palpebrae superioris is one of the muscles of the eyelids. It arises from the inferior surface of the lesser wing of the sphenoid bone. From this point, it diverges anteriorly to insert into the:
- skin of the upper eyelid
- superior tarsal plate
The fibres inserting into the superior tarsal plate are largely smooth muscle and they are supplied by the sympathetic division of the autonomic nervous system. Often, these muscle fibres are considered as separate from the rest and are termed 'the superior tarsal muscle'. The rest of the muscle is innervated by the superior division of the oculomotor nerve (CN III).
Levator palpebrae superioris acts to elevate and retract the upper eyelid. Dysfunction of the muscle results in either partial or complete ptosis with or without loss of active eyelid elevation. Potential aetiologies include:
- injury to the sympathetic innervation arising anywhere from brain through the superior cervical ganglion to the muscle; it may be present with a Horner's Syndrome
- oculomotor nerve palsy (CN III)
Alternatively, in a facial nerve palsy (CN VII), the action of levator palpebrae superioris may go unbalanced due to the loss of function of the orbicularis oculi muscle. This results in persistent eye opening.