Final answer:
The two main pelvic floor/diaphragm muscles are the levator ani and the ischiococcygeus. These muscles support the pelvic organs, resist intra-abdominal pressure, and create sphincters for the urethra and anus.
Step-by-step explanation:
The two main pelvic floor/diaphragm muscles are the levator ani and the ischiococcygeus. The levator ani, which consists of two skeletal muscles called the pubococcygeus and the iliococcygeus, is considered the most important muscle of the pelvic floor. It supports the pelvic organs, resists intra-abdominal pressure, and creates skeletal muscle sphincters at the urethra and anus. The ischiococcygeus muscle also plays a role in supporting the pelvic viscera and assisting in childbirth.