Teaching NeuroImage: Palmaris Brevis Sign

What is it about?

Clinical clues are important for the precise localization of ulnar nerve lesions. Distal ulnar nerve lesions at the wrist affect the superficial and deep branches. More distal lesions can selectively affect the superficial or the deep branch. The superficial branch is unique in that it contains not only sensory fascicles (digit 5 and the ulnar side of digit 4), but also innervates the palmaris brevis muscle (which causes puckering of hypothenar skin). Intact palmaris brevis contraction in the presence of weakness of ulnar nerve-innervated intrinsic hand muscles localizes the site of the lesion to the deep motor branch. This paper shows a teaching image illustrating the palmaris brevis sign in a patient who sustained a drill bit injury to the proximal hypothenar palm.

Featured Image

Why is it important?

A rare clinical sign highly useful for the localization of distal ulnar nerve lesions, shown as a teaching image

Perspectives