What is the sacroiliac joint?

The sacroiliac joint is the place where the low back meets the pelvis. It is the connection of the sacrum, the lowermost part of the spine, and the ilium, the wide set of bones that form the waist.

Your sacroiliac joint gets a workout whenever you bend forward from the trunk. You use your sacroiliac joint when you work over a counter, lean over a sink, make the bed, or wash the dishes.