# Backwards and Bilateral: An Unexpected Variation of the Palmaris Longus

## TL;DR

This study reports a rare anatomical variation of the palmaris longus muscle that could affect wrist function and increase nerve compression risks.

## Contribution

The study identifies a previously rare bilateral reversed palmaris longus configuration and discusses its clinical implications.

## Key findings

- A reversed palmaris longus configuration was found bilaterally during cadaveric dissection.
- This variation may alter wrist biomechanics and increase the risk of carpal tunnel syndrome.
- The study emphasizes the need for further research on how such anatomical variations affect forearm function.

## Abstract

The palmaris longus (PL) is a slender forearm muscle that contributes to wrist flexion and tensioning of the palmar aponeurosis, though its presence and configuration can vary among individuals. This study describes a rare occurrence of bilateral reversed palmaris longus (RPL) identified during routine cadaveric dissection, in which the muscle belly is positioned distally, and the tendon extends proximally. Such a configuration has the potential to alter wrist biomechanics and may increase the risk of nerve compression syndromes, including carpal tunnel syndrome. The study highlights the clinical significance of RPL, particularly in surgical situations where tendon grafting or carpal tunnel release could be affected by the reversed anatomy, and emphasizes the importance of further investigation into PL width variations to better understand their relationship to forearm function and nerve compression risk.