An accessory flexor digiti minimi brevis or flexor digiti minimi longus?

Abstract

During routine gross anatomical dissection of the right forearm and hand region of a 61 year old male cadaver, an unusual muscle originating from the tendon of palmaris longus muscle was observed. This muscle originated 3.1 cm proximal to the proximal end of flexor retinaculum and coursed superficial to the retinaculum to reach the hypothenar region. In the hypothenar region, 5.2 cm distal to the proximal end of flexor retinaculum, the muscle fibers became tendinous and this tendon was inserted to the medial side of the base of fifth proximal phalanx. In this cadaver, muscle fibers of flexor digiti minimi brevis was also inserted to the medial side of this variant tendon in a unipennate manner and reached to its final insertion. Our case is unique and the possibility of the presence of such an anomalous huge muscle must always be remembered by the clinicians when a patient has findings of ulnar nerve compression syndrome or hypovascularity symptoms in the hand area due to the compression of ulnar artery.Keywords: accessory flexor digiti minimi brevis muscle; anatomy; flexor digiti minimi longus muscle; human cadaver variation Anatomy 2015;9(1): [45][46][47]

Anomalous muscles and nerves in the hand of a 94-year-old cadaver—A case report

“…Published variations of ADM include having abnormal origins, being united with flexor digiti minimi, having one, two, or three muscle bellies, or being absent [1]. A flexor digiti minimi longus (FDML), an extra flexor of the 5th digit, has been reported in the past although rarely [2,3]. Anomalous FDML muscles have been described as originating from the ulnar tuberosity, the intracompartmental septum, or the tendon of palmaris longus.…”

“…Anomalous FDML muscles have been described as originating from the ulnar tuberosity, the intracompartmental septum, or the tendon of palmaris longus. The tendon of the FDML may pass through the carpal tunnel, Guyon’s canal, or superficial to the flexor retinaculum [[2], [3], [4]]. The common denominator is that the muscle fibers run in such a way that it would function similarly to FDMB, to flex the 5th digit.…”