Sacroiliac joint dysfunction (often called an "SIJ blockage") describes a reversible functional disorder of the sacroiliac joint accompanied by reflex tension of the surrounding muscles and reduced mobility. The term "blockage" is clinical in origin and should not be equated with a mechanical jamming.
Typical are one-sided pains in the region of the sacroiliac transition, which can radiate into the buttock or the back of the thigh. Provocation tests such as the Mennell test or the forward-flexion phenomenon can provide clues during examination. The diagnosis is made clinically and assessed in the context of the entire spine.