Pelvic Floor Muscles: Anatomy, Function, and Treatment

The pelvic floor muscles stretch from the pubic bone to the tailbone and side to side. Often referred to as the core, these muscles help maintain the spine's stability and support organs located in the pelvis.

Men and women can suffer from pelvic floor dysfunction affecting the bladder, vagina, prostate, and rectum due to damaged or weakened pelvic floor muscles. There are several ways to treat conditions associated with pelvic floor muscles.

This article discusses the anatomy, function, and conditions associated with pelvic floor muscles.

Anatomy

The pelvic floor muscles separate the pelvic cavity from the perineum, or perineal area (area between the genitals and anus). Two gaps or holes in the muscles allow for the passage of the urethra and vagina (in women), while the other gap is for the anal canal. The pelvic floor muscles attach to the bony pelvis and spine for support.

Structure and Location

Also called the pelvic diaphragm, the pelvic floor is shaped like a funnel and is made of two sets of muscles: the levator ani muscle and the coccygeus muscle. There is also a thin layer of connective tissue called fascia that covers the pelvic floor muscles.

The levator ani is composed of the following three muscles:

• Puborectalis: Forms a U shape around the anal canal, contributing to fecal continence (ability to control bowel movements)
• Iliococcygeus: Elevates the pelvic floor and anorectal canal by attaching to the coccyx, perineal body, and anococcygeal ligament
• Pubococcygeus: Makes up the bulk of the levator ani muscle and is located within the pelvic floor between the puborectalis and iliococcygeus muscles and is responsible for the stability and support of the abdominal and pelvic organs

The coccygeus muscle is located behind the levator ani muscle and is triangular. This small muscle supports the pelvic viscera, comprising the reproductive organs, bladder, and rectum.

Anatomical Variations

One study found that the shape of the pelvic floor muscles may correspond with your age, body weight in relation to height, and the size of the lower pelvic canal. Age tends to affect the female pelvic floor anatomy more than that in males. Furthermore, childbirth can cause damage to the pelvic floor muscles resulting in changes in anatomy.

Lower urinary tract dysfunction has also been linked to an anatomical variation affecting how the puborectalis muscle engages the urethra.

Function

The functions of the pelvic floor muscles are to provide stability to the core, apply resistance to intra-abdominal/pelvic pressure during coughing or lifting, maintain proper position of the pelvic organs, and provide sensation to the pelvic floor, including the genitals.

Motor Function

The pelvic floor muscles are voluntary and can be contracted and relaxed under conscious control. When contracted, the pelvic floor muscles tighten the opening of the urethra, vagina, and rectum and lift up the pelvic organs.

Relaxing the pelvic floor muscles allows for urination and bowel movements to occur. Like most voluntary muscles, some exercises can improve the motor function of the pelvic floor muscles.

Sensory Function

The pelvic splanchnic nerves, also called nervi erigentes, supply sensory function to the pelvic organs and pelvic floor muscles. Originating from the sacral nerve roots, the splanchnic nerves assist with urinating, defecating, sexual arousal, orgasm, and ejaculation. Chronic pelvic pain also arises from the pelvic nerves.

The main nerve of the pelvic floor muscles is the pudendal nerve. The pudendal nerve is found bilaterally (on both sides of the body) and arises from the sacral plexus. The pudendal nerve is responsible for urethral and anal sphincter contractions and provides sensory information to the penis, vagina, perineum, and anus. Damage to the pudendal nerve can cause pelvic pain, numbness, and pelvic organ dysfunction.

Associated Conditions

Pelvic floor disorders (PFDs) are a group of conditions that are caused by weak or damaged pelvic floor muscles. Approximately 47% of women have at least one PFD. Pregnancy, childbirth, radiation, surgery, age, and having obesity are common causes. PFDs caused by dysfunctional pelvic floor muscles include:

• Pelvic organ prolapse (POP): When pelvic organs (uterus, cervix, vagina, prostate, bladder, urethra, and rectum) drop from their usual position
• Cystocele: When the bladder prolapses into the vaginal canal
• Enterocele: When the small intestine bulges into the vagina
  
• Rectocele: When the rectum protrudes into the vagina
• Urinary incontinence: Unintentional loss of urine from the bladder
• Pelvic pain
• Sexual dysfunction: Inability to become aroused, reach orgasm, or ejaculate

Treatment

Treatment of PFDs can be challenging depending on the cause. Ways to treat PFDs include:

• Pelvic floor exercises: Keeping the pelvic floor muscles strong can help prevent urinary incontinence and keep pelvic organs in place. Kegel exercises involve squeezing and relaxing the pelvic floor muscles.
• Pelvic floor rehabilitation: Techniques such as massage, biofeedback, electrical neural stimulation, and pessary use may help treat PFDs.
• Lifestyle: Maintaining a healthy weight by exercising, getting enough fluids, and eating a fiber-rich diet can help prevent constipation and bowel incontinence associated with pelvic floor dysfunction.
• Medication: Nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce pelvic pain, and laxatives relieve constipation, improving the side effects of PFDs.
• Surgery: Although surgery may not be able to cure PFDs, it can treat the consequences of the disorder. Surgical correction of organ prolapse can provide comfort and maintan pelvic organ function in people with PFDs.

Not all treatments for PFDs are safe. Kegel exercises may be contraindicated in people with pelvic floor muscle injuries; therefore, always consult your healthcare provider before treating a PFD.

Summary

The pelvic floor muscles are vital to urinating, having bowel movements, sexual pleasure, and pelvic organ support. Located in the lower portion of the pelvis, the levator ani muscle makes up the largest part of the pelvic floor muscles. The pelvic splanchnic nerves supply the pelvic floor muscles with motor and sensory information.

Weakened or damaged pelvic floor muscles can lead to pelvic disorders requiring treatment. Speak to a healthcare provider if you have pelvic floor muscle dysfunction symptoms, including pelvic pain, urinary and bowel incontinence, or an inability to enjoy intercourse.