The sacroiliac joints are located in the lower back, connecting the sacrum at the base of the spine to the iliac bones of the pelvis. These joints play a crucial role in transferring weight and forces between the upper body and the legs during activities like walking and running. Each sacroiliac joint is surrounded by strong ligaments, providing stability while allowing for a small amount of movement. This limited mobility helps absorb shock and reduce stress on the spine. Dysfunction or inflammation in these joints can lead to pain in the lower back and hips.