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Levator palpebrae superioris muscle

The levator palpebrae superioris muscle (LPS) is a slender, elongated muscle located in the upper orbit, primarily responsible for elevating the upper eyelid. It plays a crucial role in eyelid movement, enabling the opening of the eye and contributing to facial expression. Anatomically, the muscle originates from the lesser wing of the sphenoid bone, just above the optic canal, and extends forward to insert into the upper eyelid and the superior tarsal plate. Dysfunction of this muscle is commonly associated with ptosis (drooping of the upper eyelid).

Synonyms

  • LPS muscle

  • Upper eyelid elevator

  • Levator muscle of the eyelid

Function

  • Elevates the upper eyelid to open the eye

  • Contributes to nonverbal facial expression

  • Facilitates visual field expansion by raising the upper eyelid

  • Works in coordination with the superior tarsal (Müller’s) muscle for full eyelid elevation

MRI Appearance

  • T1-weighted images:

    • Appears as a thin, linear structure with isointense to mildly hypointense signal compared to adjacent extraocular muscles

    • Good anatomical delineation in orbital coronal or axial planes

  • T2-weighted images:

    • Shows isointense to mildly hyperintense signal relative to muscle

    • Any edema, inflammation, or atrophy may cause increased signal intensity

  • STIR (Short Tau Inversion Recovery):

    • The posterior band appears slightly hyperintense (mildly bright) compared to T2 and T1 due to fat suppression.

    • Pathological changes such as myositis or infiltration result in high signal intensity (hyperintense compared to normal muscle)

CT Appearance

  • Seen as a thin, soft tissue density muscle above the superior rectus muscle in the upper orbit

  • Clearly identified on coronal and axial CT, best visualized when contrasted with orbital fat

MRI images

Levator palpebrae superioris muscle mri coronal image