The sacroiliac joint (SIJ) is a plain synovial joint through which the body weight is transmitted from the trunk to the lower
extremity. Bones forming the joint are auricular surface of the sacrum and ilium. SIJ has gained its importance towards
anatomical and radiological studies in relation to the treating aspects in ankylosis and other degenerative diseases of the
joint. This complex joint shows numerous structural variations with the increase of age. The present case describes
unilateral ankylosis of SIJ of right side. The postero-superior interosseous part of the SIJ was completely fused, and the
anterior, posterior and interosseous sacroiliac ligaments were ossified. These ossifications may cause painful and restricted
movements of the joints of pelvis. Anatomical and radiological knowledge of ankylosis of SIJ may be helpful for clinicians,
radiologists and surgeons for differential diagnosis and can be implicated in the development of innovative treatments of
sacroiliac and perineal pains.
sacro-iliac joint, ankylosis, anterior, posterior and interosseus sacroiliac ligaments, pudendal nerve.