This document discusses sacroiliac joint dysfunction. It covers anatomy of the sacrum, sacral motions including nutation and counter nutation, and types of sacral somatic dysfunction. Diagnosis involves history, physical exam including special tests like Faber, Gillett and Yeoman's tests, and sacroiliac joint injections which are the gold standard. Management can include soft tissue techniques, muscle energy techniques, counterstrain and other osteopathic manipulative medicine.