47 - The Prevalence of the Extensor Pollicis Et Indicis Communis Muscle

Poster Board Number: 47
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Odd poster #s – first hour
Even poster #s – second hour

Co-authors:

Halee Sowinski - Department of Pathology, Anatomy, and Laboratory Medicine (PALM); West Virginia University School of Medicine; Joy Balta - Anatomy Learning Institute, Point Loma Nazarene University; Amanda Troy - College of Osteopathic Medicine, Duquesne University; Matthew Zdilla - Department of Pathology, Anatomy, and Laboratory Medicine (PALM); West Virginia University School of Medicine

Abstract Body : The extensor pollicis et indicis communis is a variable extrinsic muscle of the hand which contributes to both the extension of the index finger and extension of the thumb. The extensor pollicis et indicis communis may have biomechanical implications. Likewise, the muscle has clinical implications and may be useful as a candidate tendon for transfer surgery and tendon repair. Despite the potential importance of the muscle variation, it has limited large-scale cross-sectional data regarding its prevalence. Therefore, this report details the prevalence of the extensor pollicis et indicis communis muscle in a sample of 498 limbs from willed body donors. The variant muscles were identified in 1.6% (4:249) of left upper extremities and 2.0% (5:249) of right upper extremities. In total, the extensor pollicis et indicis communis was identified in 1.8% (9:498) of all limbs included for study. Among the seven individuals who possessed the muscle, the variation was found to be unilateral twice on the left side (2:7; 29%) and three times on the right side (3:7; 43%). In two individuals (2:7; 29%), the muscle variant was found bilaterally. This report contributes valuable information regarding the prevalence and laterality of the extensor pollicis et indicis communis muscle.