20 Muscles of the Pelvic Floor

Pelvic Floor:

If you have ever reclined in a nice hammock you will know there is a balance between flexibility and rigidity to ensure you are comfortable yet safe. The pelvic floor consists of several muscles and connective tissues that support the organs in your pelvis like your bladder, bowl and internal reproductive organs. These muscles help to squeeze and relax your pelvis and even coordinate with organs like your urethra –contracting or relaxing can help excretion or urination. Like a hammock the pelvic floor must be flexible to allow for adjustment yet strong enough to maintain structure.

This subchapter will deal with the array of pelvic floor muscles and perineal muscles.

Note: Perineal refers to the area between the anus and genitalia.

Pelvic Floor Muscles:

While there are several muscle groups the muscle which forms most of the pelvic floor is the levator ani group, made of 3 distinct muscles:

1. Pubococcygeus: Stretches from the pubic bone to the coccyx forming the largest portion of the levator ani group
2. Puborectalis: The U-shaped muscle which forms a sling around the rectum which is critical for bowel control as this forms the anorectal angle which prevents involuntary defecation.
3. Iliococcygeus: The most posterior muscle which runs from the ischial spine of the pelvis to the coccyx. While present, the iliococcygeus is often less involved in support than the latter two muscles.

The coccygeus muscle is a smaller, triangular muscle that lies posterior to the levator ani that stretches from the ischial spine to the lower sacrum and coccyx. The coccygeus works in tandem with the levator ani to support the pelvic viscera and support the sacrococcygeal joint.

The Perineal Muscles:

The perineal muscles are located within the region between the pubic symphysis and the coccyx and between the thighs forming the external genitalia and the anus. Below are some key perineal muscles:

• External anal sphincter: encircles the anus and allows voluntary control over defecation
• Ischiocavrnosum: present in both sexes and helps maintain erection through compressing veins around erectile tissues in males (penis) and females (clitoris).
• Bulbospongiosus:
  • In males, it surrounds the base of the penis and aids in erections and urination
  • In females, it surrounds the vaginal opening and contributes to vaginal contraction and clitoral erection.