Bones of the Pelvis

There are three bones of the pelvis: the hip bone, sacrum and coccyx. These bones connect the axial skeleton to the lower limbs, and therefore play a role in bearing the weight of the upper body. These bones also act as attachments for many muscles and ligaments within the pelvis and lower limbs.

The hip bone has three parts: the ilium, pubis and ischium. These are separated by cartilage at birth and fuse during puberty.

The sacrum is located inferiorly to the spinal vertebrae, and posteriorly within the pelvis. It is formed by the fusion of five sacral vertebrae, and transmits the sacral nerve fibres of the cauda equina.

The coccyx, commonly referred to as the tailbone, is the smallest of the pelvic bones, and sits inferiorly to the sacrum. It does not serve any function, but acts as a point of attachment for a few muscles and ligaments. 

The pelvic girdle is the ring shaped collection of these bones at the base of the spine.

In this section, learn more about the bones of the pelvis – the hip, sacrum and coccyx, and the pelvic girdle.