The sacroiliac joint links the spine with the pelvis. When inflamed, symptoms include low back pain and stiffness that may spread into the buttocks and pelvis. Arthritis may also develop in other joints, such as a knee or ankle. When this happens, it`s as if the inflammation present in the digestive tract - the hallmark of Crohn`s disease - spills over into the joints. The same thing can happen with ulcerative colitis, another type of inflammatory bowel disease.
Source: Harvard Health Publishing
