What Are Your Sacroiliac Joints?
Your SI joints are located where the sacrum and ilium meet. The sacrum is the triangle-shaped bone near the bottom of your spine, just above your coccyx, or tailbone.
The SI joints support the weight of your body, distributing it across the pelvis. This acts as a shock absorber and reduces the pressure on your spine.
The bones of the SI joints are jagged. These jagged edges help them stay in alignment. Spaces between the bones are filled with fluid, which provides lubrication. These spaces are also filled with free nerve endings, which send pain signals to the brain.
Read more at: https://www.healthline.com/health/si-joint-pain#symptoms
