The internal sacro-sciatic ligament belongs to the medial ligaments of the pelvis. The following sources of these ligaments exist: the medial group of the thoracolumbar fascia, the fascia on the lateral surface of the half. Their purpose is to limit extreme extension of both the hip and pelvis. One end of the ligament is attached to the concave part of the sacral wing. The other end is attached to the superior ramus of the ischium. Most often, disruption of these ligaments occurs during childbirth. During labor, they are stretched and torn, which leads to damage to the pelvic organs. To treat and prevent ligament rupture, a caesarean section is performed. There is also the opposite problem - weak internal sacro-sciatic ligaments, which can lead to damage to the elements of the spinal cord and hip joints, and impaired blood supply.