Anatomical variations of the abductor pollicis longus: a pilot study

Abstract

Background:The abductor pollicis longus (APL) originates from the lateral part of the dorsal surface of the body of the ulna below the insertion of the anconeus muscle, from the interosseous membrane, and from the middle third of the dorsal surface of the body of the radius. However, the number of its accessory bands and their insertion vary considerably.Material and methods: Fifty upper limbs (2 paired, 31 male, 19 female) were obtained from adult Caucasian cadavers, and fixed in 10 % formalin solution before examination Results: The APL muscle was present in all specimens. The muscles were divided into three main categories, with Type II and III being dived into subtypes. Type I was characterized by a single distal attachment, with the tendon inserting to the base of the I metacarpal bone. Type II was characterized by a bifurcated distal attachment, with the main tendon inserting to the base of the first metacarpal bone; this type was divided into three subtypes (A-C). Type III was characterized by the main tendons inserting to the base of the first metacarpal bone, while the accessory band was characterized by mergers (fusion) with other tendons. This type was divided into two subtypes (A-B). Conclusions:The abductor pollicis longus is characterized by high morphological variability.

Multi-Tendon Abductor Pollicis Longus Muscle and its Clinical Significance

“…The presence of additional structures can lead to compression syndromes, tendovaginitis with limb overload, osteoarthritis and others. De Quervain syndrome, first carpometacarpal arthritis and trapeziometacarpal subluxation are examples of complications that may develop as a result of the described variations in the APL muscle [7,10]. The knowledge of accessory muscle tendons can be used for the needs of plastic surgery.…”

“…Anatomical variations in this area and the APL respectively, are characteristic for a variety of pathology f.e De Quervain's Syndrome, first carpometacarpal arthritis, and trapeziometacarpal subluxation [7,10]. They might influence joint functionality, which underlines the significance of upper limb anomalies in the operative clinical setting and eventually alter therapeutic outcomes [8].…”

“…Abductor pollicis longus muscle (APL), extensor pollicis brevis and extensor pollicis longus comprise the posterior antebrachial muscle group of the thumb. The latter executes movements in the carpal and the trapeziometacarpal joints and promotes their stability [1,5,6,7].…”

The Anatomy of the Tendon of Abductor Pollicis Longus and its Morphological Variations: An Anatomical Approach Emphasizing the Clinical Relevance

“…However, during the last seventy years, several studies (Lacey et al, 1951;Coleman et al, 1953;Baba, 1954;Jackson et al, 1986;Brunelli et al, 1991;Khoury et al, 1991;van Oudenaarde, 1991;Yuksel et al, 1992;Fabrizio et al, 1996;Dos Remédios et al, 2005;Shiraishi et al, 2005;Kulthanan et al, 2007;Paul et al, 2007;Mehta et al, 2009;Bravo et al, 2010;Roy et al, 2012;El-Beshbishy et al, 2013;Thwin et al, 2014;Tewari et al, 2015;Lee et al, 2017;Palatty et al, 2018;Xu et al, 2018;Karauda et al, 2020;Deivasigamani et al, 2021;Gnanasekaran et al, 2021) have shown that the APL tendon is much more variable than reports from the classical literature suggests, reaching proportions of 74.41 % and 85 % according to Roy et al (2012) and Bravo et al (2010) respectively. The anatomical diversity ranges from supernumerary tendons to variations of the point of insertion or tendons that divide themselves into various tendinous slips.…”

Case report of a bifurcated fibular (lateral) collateral ligament: which band is the dominant one?

“…Anatomical structures tend to vary and can surprise us with their morphological variations [12,26,27]. Such fluctuations are quite common among ligaments, muscles, and their tendons [1,6,7,11,[21][22][23][24][25]. Although scientists know a lot about the morphology of the FCL, it can still present some new features.…”