The lumbosacral joint is an important anatomical structure that connects the lumbar spine to the sacral bone in the pelvis region. This joint is critical for supporting the body's weight and facilitating movement. There are several synonyms for the lumbosacral joint, including the sacrolumbar joint, the lumbar-sacral joint, and the LS joint. The sacrum and lumbar vertebrae articulate at the lumbosacral joint, making it a vital part of the spine's overall function. Injuries or conditions that affect the lumbosacral joint can cause significant pain and disability. It is important to seek medical attention if you experience any symptoms in this area.