There are two Sacroiliac (SI) Joints are on either side of the spine, beneath the lumbar region and above the sacral. They connect the spine to the pelvis. This is a very strong, limited-motion joint, reinforced by strong ligaments because its duty is to transfer all the forces of the upper body onto the hips and legs. Doctors are unclear of the exact cause of SI Pain but most attribute it to unnatural motion occurring at the joint. This could mean too much mobility causing instability, or too little causing stiffness. SI Joint Dysfunction causes pain in the lower back, which can possibly radiate down the groin and leg. BioSkin back Braces address these symptoms with vectored, targeted compression that alleviates pain and relieves pressure from the low back.