Coccyx

The vestigial guman tail,is highly variable in shape, with three to five (most often four) variably fused segments. The rudimentary vertebrae of coccyx show articular and transverse process superiorley,but t hey lack pedicles, laminae, and spinous processes. The sacral articulation is via the superior coccygeal body as well as a relatively large pair of tubercles called the Cornau. The latter are rudimentary articular processes that contact the sacrum. The coccyx may fuse with the sacrum late in life.

As with the sacrumm the individual vartebral elements of the coccyx decrease in size inferiorly, and horizonyal lines of fusion can be seen between adjacent coccylgeal vertebrae. The coccyx pelvic muscles and ligaments.