North American Registry of Midwives (NARM) Practice Exam

Which pelvic muscle comprises the largest portion of the pelvic floor?

1. Deep transverse perineal

2. Superficial transverse perineal

3. Pubic bone

4. Levator ani

The correct answer is: Levator ani

The levator ani muscle group is indeed the largest portion of the pelvic floor. This muscle group consists of several muscles, including the pubococcygeus, iliococcygeus, and ischiococcygeus. It plays a crucial role in supporting the pelvic organs, maintaining continence, and assisting with childbirth. The levator ani forms a significant part of the pelvic diaphragm, which acts to stabilize and support the pelvic cavity. This support is vital for not only the integrity of the pelvic organs but also for functioning during various activities such as standing, walking, and lifting. In contrast, the deep and superficial transverse perineal muscles, while important for pelvic floor function, comprise smaller portions of the pelvic floor compared to the levator ani. These muscles primarily support the urogenital region but do not provide the same extensive support and coverage of the pelvic cavity. The pubic bone, while a structural component of the pelvis, is not a muscle and therefore does not contribute to the muscular support of the pelvic floor in the same manner.