Is Whitnall's ligament responsible for the curved course of the levator palpebrae superioris muscle?

Abstract

Background and purpose: The levator palpebrae superioris (LPS) muscle courses anteriosuperiorly to culminate cranial to the posteriosuperior surface of the globe from where it courses anterioinferiorly to the trasal plate. Whitnall's superior transverse ligament (STL) has been suggested to suspend the LPS at its culmination. If this was the case, one would expect the STL to be located near the culmination of the LPS. In order to elucidate this functional aspect of the STL, the spatial relation of the STL of the LPS muscle is investigated in this study.

Methods: Surface coil MRI in an oblique sagittal plane along the optic nerve was performed in 6 orbits from 3 human cadavers in which the STL was marked with synthetic material.

Results: The MR images showed that in human cadaver specimens the STL is situated in the anterior descending portion of the LPS.

Conclusion: This result suggests that the STL does not suspend the LPS at its culmination and is therefore not responsible for the curved course of the muscle.