The muscles of the pelvic floor are located at the bottom of the pelvis. These muscles attach to the pubic bone in the front and the tail bone in the back. The muscles are shaped like a sling and help to support the bladder and other organs of the pelvis. These muscles surround the anus, vagina and urethra and help to control urination, defecation and intercourse. The muscles of the pelvic floor are skeletal muscles and thus under voluntary control.