Reversed Palmaris Longus Muscle With Median Nerve Compression Symptoms: A Case Report and Review of the Literature

The palmaris longus (PL) is one of the most anatomically variable muscles in the body. Although these variations are often asymptomatic, symptoms related to nerve compression can sometimes be encountered. If treatment is indicated, correct diagnosis is important for successful management. In cases of upper extremity nerve compression, variations of the PL should be included in the differential diagnosis. We report a case of reversed PL (RPL) with symptoms of median nerve compression and review the literature, emphasizing the rare and challenging character of these lesions.

The literature review was performed using Google Scholar and PubMed databases. Keywords were "reversed palmaris longus," "reversed palmaris longus median nerve compression," "anomolous palmaris longus muscle," and "symptomatic palmaris longus." Only clinical RPL muscle cases with at least one of the symptoms of paresthesia and pain in the median nerve sensory area or swelling on the wrist were included.

In the literature review, 21 publications including 30 patients, matched the search criteria between 1973 and 2018 and were evaluated.

In carpal tunnel syndrome, in cases with atypical presentation, RPL should be considered in the differential diagnosis.