Javier Catón; Elena Martínez-Sanz; Julio Morán-Morán; Pedro López-Fernández & Jorge Murillo-González

During routine dissection of a left upper limb of a 68-year-old male human cadaver, an unusual muscle was observed originating from the radius and flexor retinaculum, and continued in the hypothenar region with the muscle belly of the abductor digiti minimi. We checked that it was an accessory abductor digiti minimi (ADM). Its muscular belly was in close relation to the median and ulnar nerves. We review the literature regarding such muscle variations and discuss the potential for compression of the median and ulnar nerves. Although the accessory ADM is usually asymptomatic and only rarely results in nerve compression, it should be taken into account by surgeons when establishing a differential diagnosis in the compression neuropathies of the median and ulnar nerves. An ultrasound scanning can help establish the differential diagnosis.

KEY WORDS: Accessory abductor digiti minimi; Entrapment; Median nerve; Ulnar nerve.

CATÓN, J.; MARTÍNEZ-SANZ, E.; MORÁN-MORÁN, J.; LÓPEZ-FERNÁNDEZ, P. & MURILLO-GONZÁLEZ, J. Músculo abductor digiti minimi accessorius como posible factor de riesgo de la compresión de los nervios mediano y ulnar. Int. J. Morphol., 38(6):1555-1559, 2020.