Transverse carpal muscle in association with carpal tunnel syndrome: Report of three cases

Abstract

Anomalous muscles of the upper extremity are common, however, symptomatic anomalies causing CTS are rare. Three cases of CTS that are believed to be caused by an anomalous muscle located palmar to the transverse carpal ligament with transversely oriented muscle bundles is presented. Despite the arguments in literature, this is certainly an anomalous muscle that can be encountered during carpal tunnel release and be problematic to manipulate when minimally invasive approaches are chosen.

Variations in the Course of the Thenar Motor Branch of the Median Nerve and Their Relationship to the Hypertrophic Muscle Overlying the Transverse Carpal Ligament

“…8 Some also believe that this muscle has a role in the pathogenesis of carpal tunnel syndrome. 5,7 Because of this controversy, the muscle has been named differently by various authors, such as the anomalous origin of thenar/hypothenar muscles, 9 the broad origin of thenar/hypothenar muscles from the TCL, 10 the hypertrophic muscle of the TCL, 11 and musculus transversus carpi. 6 Note that this muscle has no relationship to the palmaris brevis, which is a subcutaneous muscle arising from the ulnar border of the palmar aponeurosis and pisiform, and inserting into ulnar skin and the fascia of hypothenar muscles.…”

“…[5][6][7][8] Some believe that this is a separate anomalous muscle, 6 whereas others believe it is mostly a hypertrophic thenar muscle origin from the TCL. 8 Some also believe that this muscle has a role in the pathogenesis of carpal tunnel syndrome.…”

The Impact of Muscular Variation on the Neurodynamic Test for the Median Nerve in a Healthy Population With Langer's Axillary Arch

“…Among these variants are Struthers's ligament, aberrant muscles in and around the carpal tunnel, and, of course, LAA itself. [31][32][33][34][35] In most of these reports, the variants are encountered during surgical procedures releasing the nerve from compression. In the present study, however, subjects with LAA were selected from a healthy population.…”

The Effect of Dividing Muscles Superficial to the Transverse Carpal Ligament on Carpal Tunnel Release Outcomes

“…[5][6][7] It has been suggested that these muscles have a role in the etiology of CTS. [1][2][3][4] Division of these muscle fibers has also been implicated in contributing to pillar pain. 8 In addition, the relationship between muscle morphology and motor branch types has been highlighted recently.…”

“…4 The purpose of this study was to test the hypothesis that division of muscle fibers lying over or within the TCL in an open carpal tunnel release does not have an effect on outcomes in patients with CTS.…”