[into]The sacrum is a large wedge bone at the posterosuperior area of the cavity of the pelvis between two hip bones. Consists of five vertebrae and creates a wedge between two hip bones.[/intro]
Structure
The sacral bone has main few parts in its structure which are the:
- Base- located superiorly
- Apex- integrates with the coccyx
- Pelvic surface- facing the viscera
- Dorsal surface
- Lateral surfaces- both lateral sides of the sacral bone
- Sacral canal
Base
The base is the superior side of the bone.
- The body is wide transversally, attached to the 5th vertebra of the lumbar region at the lumbosacral angle.
- The superior articular processes are smooth and concave medially. Articulate with the 5th lumbar vertebra together with the base. Their lateral regions are attached to the mammillary processes of the lumbar bone.
- Sacral promontory lies on the anterior side of the sacrum bone.
- Oblique laminae, posteromedial sides continue the spinous tubercle.
- Triangular foramens with short and diverge pedicles on the posterolateral regions.
The ala is formed from the transverse process, has pedicles and articular processes. It projects laterally from the sacral body. The grooves on the smooth area created by the lumbosacral trunk.
The base has longitudinal ligaments on the anterior and posterior regions. The terminal fibers, which attached to the first sacral body on the dorsal and ventral sides. The