Final answer:
The levator ani muscles, including the pubococcygeus and iliococcygeus, are the muscles with left and right portions that meet on the anococcygeal ligament.
Step-by-step explanation:
The muscles that have left and right portions and meet on the anococcygeal ligament are the levator ani muscles. The levator ani is part of the pelvic diaphragm and consists of two main skeletal muscles: the pubococcygeus and the iliococcygeus. This muscle group plays a crucial role in supporting the pelvic viscera, aiding in defecation, and assisting in childbirth.