Double Gantzer's Muscles by Four Muscle Bellies and Its Clinical Significance: A Case Report

Abstract

: The Gantzer's muscle (GM) is an additional muscle in the forearm as the accessory head of the flexor pollicis longus (FPL) and accessory head of the flexor digitorum profundus (FDP). We reported a rare case of double GM formed by four muscle bellies. From the dorsal part of flexor digitorum superficialis, small four bellies formed two muscles merging to FDP and FPL, as GMs. These accessory heads of FDP and FPL crossed the ulnar artery and the median nerve, respectively. These additional muscles in the forearm flexor compartment are rare and its clinical and embryological significances should be considered.

Accessory head of flexor pollicis longus in Jeju islander cadavers

“…7) Its incidence was revealed more commonly in men than in women, and more frequent on the right forearm than on the left forearm. Consistent with previous studies, [3][4][5][6][7][8] the overall incidence of the AHFPL obtained in this study was high and more frequent on the right forearm than on the left forearm.…”

“…In 1813, the accessory head of the flexor pollicis longus (AHFPL) was first described by CFL Gantzer, 1) since then it has been subsequently studied by a number of researchers. [2][3][4][5][6][7][8] AHFPL contributes to anterior interosseous nerve palsy through the compression of the nerve. The patient who has anterior interosseous neuropathy cannot make an "okay sign" with the thumb and forefinger.…”