The pelvis is formed by bones and muscles. The back wall is formed by the sacrum and piriformis muscle, the side walls are the obturator internus muscles, and the front wall is the symphysis pubis. The floor is formed by the levator ani and coccygeus muscles covering the sacrospinous ligaments. The pelvic diaphragm consists of the levator ani muscles and coccygeus muscle. It contains openings for the urethra, vagina, and anal canal. The pelvic viscera are supported by connective tissues like the cardinal and uterosacral ligaments.