As a child, the sacrum is made up of five different bones that fuse into one as an adult. It forms joints with each of the hipbones and aids in the stabilization of the pelvis. Similarly, the Coccyx begins as three, four, or five bones that fuse into one when the child becomes an adult. These bones are often referred to as the tailbone or the base bone.

Nerves exiting from the Sacrum and the Coccyx connect to tissues and organs in that area. Muscles related to these nerves include the buttocks, hips and parts of the thigh and leg.

These nerves control the rectum and parts of the pelvic tissue as well as other organs and tissues. Problems resulting from subluxation in this part of the spine include sacroiliac conditions, hemorrhoids, scoliosis, and pain when sitting.