Pelvic digit or rib

A pelvic digit, pelvic finger, or pelvic rib is a rare congenital abnormality in humans, in which bone tissue develops in the soft tissue near the pelvis, resembling a rib or finger and often divided into one or more segments with pseudo-articulations. Pelvic digits are typically benign and asymptomatic, and are usually discovered accidentally. [Source: Wikipedia ]