The sacrum is a triangular-shaped bone located at the base of the vertebral column, situated between the lumbar spine and the coccyx (tailbone). It is formed by the fusion of five vertebrae, labeled S1 to S5, and plays a crucial role in connecting the spine to the pelvis.
Key Functions and Anatomy
- Support and Stability: The sacrum forms the back wall of the pelvis, providing support for vital body organs, including the bladder, rectum, and reproductive organs. It helps distribute the weight of the upper body to the lower limbs during activities such as standing and walking.
- Sacroiliac Joints: The sacrum connects to the pelvis at the sacroiliac joints, which contribute to the stability of the lower back and pelvis. These joints allow for limited movement and play a role in absorbing shock during physical activities.
- Muscle Attachment: Several muscles, including the gluteus maximus and piriformis, attach to the sacrum, aiding in movement and posture.
Clinical Significance
Conditions affecting the sacrum can lead to pain and mobility issues, such as sacroiliac joint dysfunction and piriformis syndrome. Proper function of the sacrum is essential for overall spinal health and stability.