Sacrum
Os sacrum
SkeletalSkeletonPelvis
- What it is
- Wedge-shaped bone of five fused sacral vertebrae, curved concave-forward, with four pairs of sacral foramina and a median crest behind.
- Function
- Transmits the weight of the trunk to the hip bones through the sacroiliac joints and forms the back wall of the pelvis.
- Size
- ≈ 105 mm wide at the base, 110 mm tall
- Clinical note
- The sacral promontory (front edge of S1) is an obstetric landmark for measuring the pelvic inlet.