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 sacrum Sacrum and coccyx. The sacrum is the portion above the red line. Sacrum, pelvic surface. Diagrams from Gray's Anatomy A large irregular triangule shaped bone in the lower part of the spinal column. It is made of five fused vertebrae (sacral vertebrae). The sacrum's broad upper part articulates with the fifth (lowest) lumbar vertebra. Between the two is a wedge-shaped intervertebral disk called the lumbosacral disk. The narrow lower part of the sacrum articulates with the coccyx. The spinal canal extends into the sacrum and the sacral nerves exit the canal through bony foramina (openings). The sides of the sacrum are connected by the sacroiliac joints to each ilium (the largest of the bones that form the pelvis. The sacrum thus sits like a wedge in the center of the back of the pelvis. Many back problems occur where the lumbar and sacral region of the spine connect because certain activities subject this region to a lot of stress. 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