Final answer:
The main muscle of the pelvic floor is the levator ani, consisting of the pubococcygeus and the iliococcygeus. It supports the pelvic viscera and creates sphincters for the urethra and anus.
Step-by-step explanation:
The main muscle of the pelvic floor is the levator ani. It consists of two skeletal muscles, the pubococcygeus and the iliococcygeus. The levator ani supports the pelvic viscera, resists intra-abdominal pressure, and creates skeletal muscle sphincters at the urethra and anus.