Final answer:
The Sacroiliac Joint (SI Joint) is supported by the anterior and posterior sacroiliac ligaments and aids in stabilizing the pelvis, especially during weight bearing by the body.
Step-by-step explanation:
The Sacroiliac Joint (SI Joint) is a joint formed by the articulation between the sacrum and the ilium portions of the hip bone. It is supported by several ligaments, including the anterior sacroiliac ligament on the joint's anterior side and the posterior sacroiliac ligament on its posterior side. These ligaments, along with the sacrospinous ligament and the sacrotuberous ligament, maintain the stability and carry the weight of the body. The sacrospinous ligament runs from the sacrum to the ischial spine, whereas the sacrotuberous ligament runs from the sacrum to the ischial tuberosity. These contribute to the lesser and greater sciatic foramina formations.