Eleven bony pelves were studied in an attempt to find an ideal approach for needle placement into the sacroiliac joint and to describe the unique anatomy of the sacroiliac joint relative to sacroiliac joint injection. A posterior approach starting 2 cm to 3 cm inferior to the posterior superior iliac spine, angled 20 degrees to 30 degrees laterally, relative to the sagittal plane, and 10 degrees to 20 degrees inferiorly, relative to the transverse plane, was found to be the best approach to the intra-articular portion of the sacroiliac joint.