RESUMO
Occurrence of abnormal muscles in the pelvic wall is very rare. During a routine dissection of the pelvic wall, an abnormal muscle referred to as sacrococcygeus ventralis was noted in a 65-year-old South Indian cadaver. The fleshy fibers of the muscle were arising from the lateral part of the ventral surface of the sacrum at the level of S3 segment. The muscle passed downwards in front of the S4 and S5 sacral segments, halfway through its course it became tendinous and finally became inserted in the ventral surface of the coccyx. Sacrococcygeus ventralis is a muscle which is well developed in animals where it acts on their tail. In human beings, sacrococcygeus ventralis is seen only during fetal life. A rare case of its persistence in an adult pelvic wall is reported and discussed here.