The sacrum is one complete bone roughly triangular in shape, which joins together in one fused mass the five sacral vertebra of the pelvic region. It is located in a vertical position, joined to the fifth and last lumbar vertebra
above and the coccyx
below. The sacrum is wedged between the two iliac bones, creating the pelvis
. Its upper base is called the prominent sacrovertebral angle, and the lower part is called the apex. The vertebral canal runs through its center, containing the last nerve roots, called the cauda equina (Latin for "horse's tail").
Original article published by
. Translated by Jeff