Palmaris profundus muscle

Palmaris profundus (also known as musculus comitans nervi mediani[1] or palmaris bitendinous[2]) is a rare anatomical variant in the anterior compartment of forearm. It was first described in 1908.[3] It is usually found incidentally in cadaveric dissection or surgery. The prevalence of the palmaris longus was reported to be one in 1600 upper limbs.[3]

Palmaris profundus
Palmaris profundus muscle originates from the lateral edge of radius and inserts to palmar aponeurosis.
OriginLateral edge of radius, ulna, flexor digitorum superficialis or medial epicondyle of humerus
InsertionPalmar aponeurosis
ArteryUlnar artery
NerveMedian nerve, anterior interosseous nerve or ulnar nerve
ActionsWrist flexor
LatinMusculus palmaris profundus
Anatomical terms of muscle


Pirola et al.[4] classified the muscle into subtypes depending on its origin: (1) from the radius, (2) from the flexor digitorum superficialis fascia, and (3) from the ulna. Though, other origins of the muscle were reported including the medial epicondyle of humerus,[1] the palmaris longus[2] and the flexor pollicis longus.[5] It runs deep to the pronator teres and lateral to the flexor digitorum superficialis. Its tendon passes beneath the flexor retinaculum through the carpal tunnel before broadening out to insert to the deep part of palmar aponeurosis.

In many cases, the muscle is contained within the same fascial sheath as the median nerve. To indicate this association, the term musculus comitans nervi mediani is often used.[1] It can also be referred to as the palmaris bitendinosus when originating from the palmaris longus.[2] It can be considered a variation of the palmaris longus, however, it may exist in addition to the palmaris longus. If both of them coexist, the aberrant palmaris profundus tends to be the deeper one.[6]

Nerve supply to the palmaris profundus varies. Innervations by the median nerve, anterior interosseous nerve or the ulnar nerve were reported.[7]

Function of the palmaris profundus is similar to the palmaris longus. It is a flexor of the wrist.

Clinical significance

The presence of the palmaris profundus is often associated with median nerve compression and carpal tunnel syndrome as available space for the median nerve decreases due to the presence of an additional tendon.[4] It may also complicate the surgical release of the carpal tunnel.

It may compress the anterior interosseous nerve, a motor branch of the median nerve, causing a condition called anterior interosseous nerve syndrome.[8]

See also


  1. Sahinoglu, K.; Cassell, M. D.; Miyauchi, R.; Bergman, R. A. (1994-06-01). "Musculus comitans nervi mediani (M. palmaris profundus)". Annals of Anatomy - Anatomischer Anzeiger. 176 (3): 229–232. doi:10.1016/s0940-9602(11)80483-8. ISSN 0940-9602. PMID 8059966.
  2. Sánchez Lorenzo, J.; Cañada, M.; Díaz, L.; Sarasúa, G. (1996-09-01). "Compression of the median nerve by an anomalous palmaris longus tendon: a case report". The Journal of Hand Surgery. 21 (5): 858–860. doi:10.1016/s0363-5023(96)80204-8. ISSN 0363-5023. PMID 8891985.
  3. Reimann, Arthur F.; Daseler, Edward H.; Anson, Barry J.; Beaton, Lindsay E. (1944-08-01). "The palmaris longus muscle and tendon. A study of 1600 extremities". The Anatomical Record. 89 (4): 495–505. doi:10.1002/ar.1090890408. ISSN 1097-0185.
  4. Pirola, Elena; Hébert-Blouin, Marie-Noëlle; Amador, Nelly; Amrami, Kimberly K.; Spinner, Robert J. (2009-09-01). "Palmaris profundus: one name, several subtypes, and a shared potential for nerve compression". Clinical Anatomy. 22 (6): 643–648. doi:10.1002/ca.20848. ISSN 1098-2353. PMID 19644968.
  5. Yoshida, Y.; Yasutaka, S.; Seki, Y. (1983-04-01). "[Flexor radialis profundus and palmaris profundus muscles in man]". Kaibogaku Zasshi. 58 (2): 59–67. ISSN 0022-7722. PMID 6637383.
  6. Park, Min Jung; Namdari, Surena; Yao, Jeffrey (2010-02-01). "Anatomic variations of the palmaris longus muscle". American Journal of Orthopedics (Belle Mead, N.J.). 39 (2): 89–94. ISSN 1934-3418. PMID 20396682.
  7. Browne, K. M.; Fauzi, Z.; O’Shaughnessy, M. (2014-10-15). "The palmaris profundus, a rare sight during carpal tunnel release". HAND. 10 (3): 559–561. doi:10.1007/s11552-014-9691-1. ISSN 1558-9447. PMC 4551639. PMID 26330796.
  8. "Anatomy Atlases: Illustrated Encyclopedia of Human Anatomic Variation: Opus I: Muscular System: Alphabetical Listing of Muscles: P: Palmaris Longus". Retrieved 2016-01-06.
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