Female pelvic diaphragm
This specimen shows the superior view of the muscles of the pelvic floor in the females.
The Levator ani and the coccygeus form the pelvic diaphragm and delineate the lower limit of the true pelvis. Laterally the obturator internus muscle covers the obturator foramen of the pelvis. The fasciae investing the muscles are continuous with visceral pelvic fascia above, perineal fascia below and obturator fascia laterally.
The levator ani is a broad muscular sheet of variable thickness which is attached to the internal surface of the true pelvis and forms a large portion of the pelvic floor. The muscle is subdivided into named portions according to their attachments and the pelvic viscera to which they are related. These parts are often referred to as separate muscles, but the boundaries between each part cannot be easily distinguished and they perform many similar physiological functions. The separate parts are referred to as the ischiococcygeus, the iliococcygeus and the pubococcygeus. Laxity in these muscles can cause the prolapse of the pelvic viscera into the perineum.
The obturator internus arises from the inner aspect of the obturator foramen, passes through the greater sciatic notch, enters the gluteal region and inserts into the upper end of the femur. It forms the lateral boundary of the lateral pelvic wall. It is covered by the obturator fascia.