A Rare Anatomical Finding of Undescribed Accessory Palmaris Longus in the Distal Forearm: A Case Report

Upper limb muscle anomalies and their clinical implications have been described frequently in the literature reviews. In this article, we are presenting a case of aberrant forearm muscle that had not been described before, and could be considered as a palmaris longus muscle variation. A 24-year-old man presented to the emergency department, Hamad General Hospital, Doha, Qatar, with right forearm laceration with multiple cut structures for which he was admitted for exploration and repair. Intraoperatively, flexor digitorum superficialis of the third, fourth, and fifth digits, flexor carpi radialis, and palmaris longus were injured‚ and all of them were repaired. We noticed an aberrant muscle—which was also injured—that originated from the distal third of the radius on its medial aspect to insert into the palmar fascia; pulling this muscle’s tendon resulted in tightening of palmar fascia‚ same as the palmaris longus. Along with the importance of deep knowledge of typical human anatomy, hand surgeons must be aware that an aberration from normal anatomy might be anticipated, to provide the best care to our patients.