Which muscle forms the pelvic floor along with the piriformis and is located posterior to the vagina and cervix?

• A. Levator ani
• B. Coccygeus
• C. Psoas major
• D. Iliopsoas

Answer: (A)

The main thing this question tests is which muscle makes up the bulk of the pelvic floor—the pelvic diaphragm that supports the pelvic organs. The levator ani is the primary component of the pelvic floor, working together with the coccygeus to form the muscular sling that closes the pelvic outlet and supports structures like the uterus, vagina, and cervix. Its fibers spread to envelop the openings and elevate and stabilize the pelvic floor, placing it just under and around the vagina and cervix. The other choices are involved in different roles: the psoas major and iliopsoas are hip flexors that pass through the pelvis but do not form the pelvic floor, and while the coccygeus is also part of the pelvic diaphragm, the levator ani is the major contributor responsible for forming the floor.