ANATOMY & PHYSIOLOGY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site coccyx Coccyx and sacrum. The coccyx is the portion below the red line. Diagram from Gray's Anatomy A small triangular bone at the base of the spinal column. The coccyx consists of four or five small bones that are ossified or fused together. It is the vestige of a tail-bone structure possessed by our evolutionary ancestors. Together with a much larger bone called the sacrum, which lies above it, the coccyx forms the back section of the pelvis. There is very little relative movement between the coccyx and sacrum. In later life, the coccyx and sacrum are commonly fused together. Related category    • ANATOMY AND PHYSIOLOGY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP