RESUMO
We report the appearance of variations of the biceps brachii muscle and describe their anatomic characteristics in our population. A prospective evaluation was conducted on cadavers at the morgue of the "Nueva Granada" Military University (UMNG) - School of Medicine in Santafe de Bogota, Colombia. Thirty-two arms of 16 cadavers were included. Anatomic description was achieved by measurements of length, width, thickness, insertions, relations, innervating branches and blood supply. A third head for the biceps brachii muscle was found in 6 arms (37.5 percent, n=16). It appeared most frequently in the right arm (31.25 percent, n=16) and found bilaterally in 2(12.5 percent, n=16) cases; arising from the lower third the humeral shaft at 12.82 ± 0.59 cms. from the external humeral condyle and with a total length of 12.9 ± 0.29 cms. These results provide an anatomic description of the characteristics of this variation in the population studied and also is the first report of this accessory head among Colombians.