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

  • 1Department of Orthopedic Surgery, Inha University Hospital, Incheon, Korea


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.


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


  • 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.

  • 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.


1. Reimann AF, Daseler EH, Anson BJ, Beaton LE. The palmaris longus muscle and tendon. A study of 1600 extremities. Anat Rec. 1944; 89:495–505.
2. Olewnik Ł, Wysiadecki G, Polguj M, Podgórski M, Jezierski H, Topol M. Anatomical variations of the palmaris longus muscle including its relation to the median nerve - a proposal for a new classification. BMC Musculoskelet Disord. 2017; 18:539.
3. Lyrtzis C, Christos L, Natsis K, Konstantinos N, Pantazis E, Evagelos P. Revision of carpal tunnel release due to palmaris longus profundus. Case Rep Orthop. 2015; 2015:616051.
4. Browne KM, Fauzi Z, O’Shaughnessy M. The palmaris profundus, a rare sight during carpal tunnel release. Hand (N Y). 2015; 10:559–61.
5. Pirola E, Hébert-Blouin MN, Amador N, Amrami KK, Spinner RJ. Palmaris profundus: one name, several subtypes, and a shared potential for nerve compression. Clin Anat. 2009; 22:643–8.
6. Jones DP. Bilateral palmaris profundus in association with bifid median nerve as a cause of failed carpal tunnel release. J Hand Surg Am. 2006; 31:741–3.
7. Yuan J, Dhanaraj ID, Ng HJH, Rajaratnam V. Accessory palmaris longus: a concise anatomic review with a relevant case study. Ann Plast Surg. 2019; 83:363–6.
8. McClelland WB Jr, Means KR Jr. Palmaris profundus tendon prohibiting endoscopic carpal tunnel release: case report. J Hand Surg Am. 2012; 37:695–8.
9. Bland JD. A neurophysiological grading scale for carpal tunnel syndrome. Muscle Nerve. 2000; 23:1280–3.
10. Kang HJ, Jung SH, Choi CH, Choi WJ, Kim SJ, Hahn SB. Carpal tunnel syndrome caused by space occupying lesions. J Korean Orthop Assoc. 2007; 42:616–22.
Full Text Links
  • AHM
export Copy
  • Twitter
  • Facebook
Similar articles
Copyright © 2024 by Korean Association of Medical Journal Editors. All rights reserved.     E-mail: