The sacroiliac joints reside in between the sacrum (the tailbone phase from the spinal column) and the notable wing-like iliac bones that form the pelvic girdle. There's two SI joints, just one within the remaining and 1 on the right (highlighted in purple inside the picture earlier mentioned), and along https://www.theorthopaedicandpainpractice.com/service/hip-groin-pain/