Craniocaudal axial view of the sacroiliac joint.

A technique that provides a craniocaudal axial view of the sacroiliac joint is described. This technique gives information about the ventral aspect of the sacroiliac joint, particularly at the level of the pelvic brim. It can demonstrate extraarticular ventral ankylosis of the joint, which is not visible or only suspected on anteroposterior films. In osteitis condensans ilii, it shows the thickness of the involved iliac bone. It is very useful for the accurate localization of paraarticular changes.