Unilateral presentation of three muscles variants in the pectoral region

In this case report, we observed a situation in which three variant muscles presented unilaterally in a single cadaver. We observed that the pectoralis major muscle had a deficient sternocostal head. Also present were two muscles rarely observed in humans, a sternalis muscle, and a pectoralis quartus muscle. The existence of these muscle variants occurring individually in humans has been described in the literature for over a century. However, this is the first report of all three variants occurring simultaneously in one individual