The Flexor Pollicis Longus and its Relation to the Anterior and Posterior Interosseous Nerves

Abstract

Sixty paired cadaver upper extremities were dissected to study the anatomy of the flexor pollicis longus in the forearm and its relation to the median and anterior interosseous nerves. An accessory head was noted in 33 (55%) of 60 specimens. The accessory head was noted to pass anterior to the anterior interosseous nerve in all specimens. The accessory head was noted to pass posterior to the median nerve in 57 specimens, and anterior to the nerve in three. Tendon or muscle anomalies were noted in eight specimens (13%), seven of which involved an anomalous attachment between the FPL and the flexor digitorum profundus of the index.

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

“…Because aFPL is a more common type, studies have been reported on neurological effects of it on MN or AIN [6,12]. Though the clinical effect of this anatomical arrangement has not been iden- tified obviously, the presence of multiple GMs may result in restricted movement of forearm flexors and subsequent pain in lower forearm [5,6]. On the other hand, GM may be used in local transfers in peripheral neuropathy [11,12].…”

“…Although the prevalence of GM was described variously, it is persistently found in about 50% of Asian [3,4]. The various origin of the GM has been shown from medial humeral epicondyle, coronoid process or dual origin from medial epicondyle and coronoid process [1][2][3][4][5]. Its insertion was constantly reported to attach to the ulnar border of the FPL and to the wrist level tendon of the FDP, respectively.…”

“…Although controversial, the presence of this muscle confers to be an important source of compression of the nerves with potential clinical significance, such as anterior interosseous nerve (AIN) syndrome or pronator teres syndrome [2][3][4][5][6]. Variable anatomical and topographical relationships between the GM and the median nerve or AIN have been studied, however, the variation pattern of the GM was also extremely different [7,8].…”

Accessory Head of Flexor Pollicis Longus Muscle and its Significance in Anterior Interosseous Nerve Syndrome: Case Report and Review

“…Attaching to the ulnar border of the FPL is a muscle belly, named variously the accessory head of the FPL (AHFPL), Gantzer's muscle, or occasional head. This variant muscle belly may be one of the structures that compress the anterior interosseous nerve causing AINS (Dellon & Mackinnon;Hemaddy et al, 1993;Al-Qattan, 1996;Shirali et al, 1998;Tabib et al, 2001). The prevalence of the AHFPL was reported variously as 73.7% (Mangini, 1960), 45% (Dellon & Mackinnon), 52% (Al-Qattan), and 55% (Shirali et al).…”

Morphological Study of Accessory Heads of Deep Flexor Muscle of Forearm

“…al (54.2%) [13] , Dellon and Mackinnon (45%) [14] , Al Qattan (52%) [15] , Jones et al (55%) [4] , Shirali et al. (55%) [16] , Gunnal et al (51.1%) [17] and Temang et al (43%) [18] .…”