Arch Hand Microsurg.  2021 Sep;26(3):166-170. 10.12790/ahm.21.0109.

Accessory Palmaris Longus Encountered during Carpal Tunnel Surgery: A Case Report

• Ko SH
• Park JS
• Lee TJ

• KMID: 2519469
• DOI: http://doi.org/10.12790/ahm.21.0109

Abstract

The accessory palmaris longus is a rare anatomical variant in the wrist and forearm, which has been reported as the cause of carpal tunnel syndrome. This paper reports a case of the accessory palmaris longus incidentally found during carpal tunnel surgery. The paucity of awareness on the accessory palmaris longus in carpal tunnel surgery may lead to accidental iatrogenic injury to the median nerve or insufficient decompression of the median nerve.

Keyword

Carpal tunnel syndrome; Palmaris longus; Anomalous muscles; Median nerve

Figure

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  Fig. 1. Intraoperative photograph of the accessory PL (AcPL) incidentally found after transcarpal ligament was released. (A, B) This abnormal muscle shared a nerve sheath with the median nerve (MN) and coexisted with the normal PL. (C) The AcPL inserted into an accessory PA (AcPA) that passed dorsal to the normal PA. PL, palmaris longus; TLC, transverse carpal ligament; PA, palmar aponeurosis.

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  Fig. 2. After resection of the accessory palmaris longus tendon. (A) The abnormal vascular markings are seen only the ulnar portion of the median nerve (arrows), corresponding to the site of compression. (B) Resected the accessory palmaris longus tendon.

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