Reversed palmaris longus muscle: a report of two cases

Abstract

The palmaris longus muscle is the most superficial muscle of the volar forearm which demonstrates significant anatomical variance. A reversed palmaris longus muscle is one such variant. Here we discuss two cases in which reversed palmaris longus was postulated as a cause of wrist discomfort.

Keywords: Reversed palmaris longus; nerve compression; wrist pain.

Figure 1.

(a) Visible swelling in the right distal volar forearm on clinical examination; (b) An axial section of an MRI scan clearly demonstrating a superficial muscle belly at the level of the distal radio-ulnar joint in keeping with a reversed palmaris longus (*); (c) A sizeable reversed palmaris longus muscle belly in right distal volar forearm.

Figure 2.

A longitudinal section of an ultra-sound clearly demonstrating a reversed palmaris longus muscle belly (*) lying onto of the flexor retinaculum. The deep flexor tendons (‡) and radial carpal joint lie inferiorly.