Hypermobility, or too much movement in the sacroiliac joints, is a result of loose ligaments supporting the joints.

Relaxin helps the pelvis spread so the baby can exit the body, but it also affects the ligaments in the feet, causing a stretching of those ligaments.

The tunnel disappears after the screw is absorbed, avoiding the ligament's bump toward the inside tunnel, which leads to gradual extension of the inside tunnel and cause the ligament flabby.