Anatomical Variation of Radial Wrist Extensor Muscles: A Study in Cadavers

Abstract

OBJECTIVE:The tendons of the extensor carpi radialis longus and brevis muscles are quite useful in tendon transfer, such as in correction of finger clawing and restoration of thumb opposition. Knowledge of additional radial wrist extensor muscle bellies with independent tendons is useful in the above-mentioned surgical procedures. METHODS:The skin, subcutaneous tissue, and antebrachial fascia of 48 (24 on the right side and 24 on left side) male upper limb forearms were dissected. The following aspects were then analyzed: (a) the presence of additional muscle bellies of radial wrist extensors, (b) the origin and insertion of the additional muscle, and (c) measurements of the muscle bellies and their tendons. RESULTS: Five out of 48 upper limbs (10.41%) had additional radial wrist extensors; this occurred in 3 out of 24 left upper limbs (12.5%) and 2 out of 24 right upper limbs (8.3%). In one of the right upper limbs, two additional muscles were found. The length and width of each additional muscle belly and its tendon ranged between 2 -15cm by 0.35 -6.4cm and 2.8 -20.8cm by 0.2 -0.5cm, respectively. The additional radial wrist extensor tendons in our study basically originated either from the extensor carpi radialis longus or brevis muscles and were inserted at the base of the 2 nd or 3 rd metacarpal bone. CONCLUSION:The present study will inform surgeons about the different varieties of additional radial wrist extensors and the frequency of their occurrence.

Anatomical Association Between Wrist Extensor Musculature and Topographical Pain Sensitivity Maps of the Elbow Area

“…Some variations in the wrist extensor muscles have been described, particularly the presence of an additional muscle 22 ; however, it is our impression that these variations would not alter the direction of the current findings. Therefore, current results should be considered with caution at this stage.…”

An unusual elbow muscle in the red howler monkey: does it deserve invention of a new name musculus contrahens cubiti?

“…(Wood, 1988;Khaledpour and Schindelmeiser, 1994;Cankur and Öz-demir, 2003;Rao et al, 2006;Nayak, 2008). The presence …”

“…of duplication of muscle, or additional head or terminal tendon has been reported in 12-50 % of individuals, the additional structures being often found in both arms (Albright and Linburg, 1978;Khaledpour and Schindelmeiser, 1994;Gümüşalan et al, 1997;Claassen and Wree, 2002;Cankur and Özdemir, 2003;Hong and Hong, 2005;Rao et al 2006;Nayak et al, 2008;Chakravarthi, 2013). More frequent, in humans, are various bifurcations.…”

Normal Sonographic Anatomy of the Wrist With Emphasis on Assessment of Tendons, Nerves, and Ligaments

“…Its tendon runs through the second extensor compartment of the wrist or, rarely, through a separated fascial tunnel beneath the extensor retinaculum (if the accessory muscle arises from the extensor carpi radialis longus) 21 . The prevalence of an additional muscle amounts to 10% to 24% of the population in cadaveric studies, with frequent bilaterality 22 , 23 . The palmaris longus is also highly variable.…”

“…21 The prevalence of an additional muscle amounts to 10% to 24% of the population in cadaveric studies, with frequent bilaterality. 22,23 The palmaris longus is also highly variable. Its agenesis may be unilateral or bilateral and occurs in 4% to 25% of individuals, with a higher prevalence in white populations.…”