The levator ani is a broad, thin muscle group that forms the large majority of the pelvic floor. This structure can be visualized as a muscular hammock stretching from the pubic bone at the front of the pelvis to the coccyx, or tailbone, at the back. It is a foundational component of the pelvic region, creating a supportive base within the bony pelvis. This muscular sheet is not a single, uniform structure but a complex of muscles that work together.
Anatomy of the Levator Ani
The levator ani is a complex of three individual muscles that function in unison: the puborectalis, pubococcygeus, and iliococcygeus. Each has a distinct location and configuration, contributing to the overall structure of the pelvic floor.
The puborectalis muscle originates on both sides of the pubic bone and forms a U-shaped sling that loops around the rectum. This specific arrangement plays a direct role in fecal continence. The pubococcygeus muscle also arises from the pubic bone and has fibers that attach to various points, including the perineal body, the prostate in males, or the vagina in females. The iliococcygeus is the most posterior part of the muscle group, originating from fascia on the obturator internus muscle and the ischial spine, and inserting on the tailbone.
Core Functions of the Levator Ani
A primary function of the levator ani is to provide support for the pelvic organs, including the bladder, the rectum, and the uterus in females or the prostate in males. This muscular sheet holds these organs in their correct positions, counteracting the downward force of gravity and increases in intra-abdominal pressure from activities like coughing or lifting.
The muscle group is also integral to maintaining both urinary and fecal continence. When the levator ani contracts, it helps to close the urethra and rectum, preventing leakage. Relaxation of the muscle is necessary to allow for urination and defecation.
Beyond support and continence, the levator ani is a component of the body’s core stabilization system. It works in coordination with the diaphragm, deep abdominal muscles, and back muscles to regulate pressure within the abdomen and pelvis. This coordinated action is important for load distribution during movement, and the muscle also has roles in sexual function and childbirth.
Levator Ani Dysfunction
Dysfunction of the levator ani can be categorized into two main states: weakness, known as hypotonicity, or excessive tightness, referred to as hypertonicity. These conditions result in different sets of symptoms and often have distinct underlying causes.
Hypotonicity, or a weakened pelvic floor, can lead to stress urinary incontinence, which is the involuntary leakage of urine during activities that increase abdominal pressure, such as laughing, coughing, or exercising. Another major condition resulting from weakness is pelvic organ prolapse, where the pelvic organs descend and may bulge into the vaginal canal.
Conversely, hypertonicity involves a state of chronic tension or overactivity in the levator ani muscles. This tightness can be a source of chronic pelvic pain and can lead to conditions like dyspareunia, or painful intercourse. Overly tense muscles can also interfere with normal bodily functions, causing difficulty in starting a stream of urine, incomplete bladder emptying, and constipation.
Several factors can contribute to the development of either hypotonicity or hypertonicity. Childbirth, particularly vaginal delivery, is a significant cause of injury and weakening of the levator ani. Other factors include the natural process of aging, chronic straining from constipation or coughing, obesity, and previous pelvic surgeries.
Maintaining Levator Ani Health
Maintaining the health of the levator ani involves exercises that focus on both controlled contraction and deliberate relaxation. Pelvic floor muscle exercises, commonly known as Kegels, are designed to strengthen these muscles by contracting and lifting them.
Just as important as strengthening is the ability to fully relax the pelvic floor muscles. For individuals with hypertonicity or muscle tightness, focusing solely on contractions can exacerbate their symptoms. “Reverse Kegels,” which involve consciously dropping and lengthening the pelvic floor, are a necessary part of a balanced routine. Techniques like diaphragmatic breathing can help facilitate this relaxation.
Because of the complexity of these muscles and the potential to worsen symptoms with improper exercise, seeking professional guidance is recommended. A healthcare provider or a specialized pelvic floor physical therapist can perform an assessment to determine whether the muscles are weak or overly tight. Based on this diagnosis, they can create a personalized exercise program tailored to the specific needs of the individual.