Last Updated: Jul 16, 2019 The sacrum is a large wedge shaped vertebra at the inferior end of the spine. It forms the solid base of the spinal column where it intersects with the hip bones to form the pelvis. The sacrum is a very strong bone that supports the weight of the upper body as it is spread across the pelvis and into the legs.
The sacrum, sometimes called the sacral spine (abbreviated S1), is a large, flat triangular-shaped bone located below L5 and in between your hip bones. Below the sacrum is the coccyx, commonly known as the tailbone.
The sacrum and coccyx are unlike other bones in your vertebral spinal column and may be involved in the cause of your lower back pain. The sacrum and coccyx are unlike other bones in your spinal column.