The sacrum is a triangular-shaped bone located at the base of the spine, between the two hip bones. It is formed by the fusion of five vertebrae (S1-S5) during childhood and adolescence. The sacrum is an important part of the pelvic girdle and plays a crucial role in the support and movement of the body.
The anatomy of the sacrum includes several features that allow it to function as part of the spine and pelvis:
- The body: This is the main part of the sacrum and is formed by the fusion of the five vertebrae. The body is triangular in shape and is wider at the top and narrower at the bottom.
- The ala: These are the bony wings that extend from the sides of the sacrum. The alae provide attachment points for the muscles and ligaments of the pelvis.
- The transverse processes: These are bony projections that extend from the sides of the sacrum and provide attachment points for the muscles and ligaments of the spine and pelvis.
- The sacral promontory: This is the bony projection at the top of the sacrum that forms the front of the pelvis.
- The sacral canal: This is a canal that runs through the center of the sacrum and contains the sacral nerves and blood vessels.