When it comes to the muscles in our pelvis, most of us don't know what they're called or what they do. Fortunately, you don't need to be an anatomy expert to understand the basics. While there are similarities between the pelvic floor muscles in men and women, this article will focus on the pelvic floor muscles in people whose biological sex assigned at birth is female. In this series, we'll take a look at the pelvic floor muscles, what they do, and why they matter.
3.) Sexual Function
4.) Orthopedic Function (and back pain)
Pelvic Floor Muscles: Layer 1
There are three layers of muscles in the pelvic floor. The first layer of muscles are the ones closest to the surface of your skin. Because they are superficially located, evaluating these muscles is minimally invasive. Some of their function can be evaluated by visually observing the pelvic floor while a patient performs certain movements such as a cough, bearing down, or attempting a Kegel.
If doing an internal assessment of this layer for women, the therapist typically inserts one gloved finger into the vaginal canal to the depth of approximately the first knuckle (anatomically called the distal interphalangeal joint (DIP)). A speculum is not needed to assess these muscles.
The Gate Keeper: Bowel & Bladder Control
The first layer's primary job is to be the gate keeper. These muscles are tasked with controlling when we allow things to pass in or out of the pelvis. While you may not actively think about contracting these muscles, they are actually "on" or contracted most of the time. Our default is for our pelvic floor muscles to be slightly contracted. This is important because we want to control when we go to the bathroom. We don't want to be leaking urine or stool all the time, so the first layer of pelvic floor muscles contract to constrict the opening of the urethra and the rectum.
When it's time to go to the bathroom, these muscles relax and allow us to empty. At least they should relax to allow us to empty. For people having trouble with emptying their bladder, who have to strain to have a bowel movement, or who have pain with initial penetration during sex (called entry pain), this is often where the problems start.
Because these muscles are "on" all the time, relaxing them can feel like work. Relaxing the muscles is the opposite of how they are usually positioned. This can be a bit of a paradox for our brains. We typically think of the "resting" state of a muscle as being the one that the muscle is in most of the time, unless we tell it to do something else. For our pelvic muscles, however, the default setting is "on", not "off".
Muscles, however, can contract at varying degrees of strength. Rather than a simple on/off switch, think about your muscles contracting on a continuum more like a dimmable light switch. Let's take a more familiar muscle, like your biceps, for example. You might slightly contract your biceps to bend your elbow while carrying a water bottle in your hand rather than letting your arm swing loosely at your side. That same bicep muscle can also contract with more force to curl a 20lbs dumbbell and raise it up to your shoulder.
The pelvic muscles work similarly, but the source of the resistance isn't a dumbbell or a water bottle. Instead, pelvic muscles have to adapt the strength of their contraction to the internal weight of the fluid in the bladder, or the stool in the colon. They're also responsible for resisting the downward abdominal pressure created by a cough, sneeze, or laugh. They even resist the pressure of your own body weight that sits on top of them.
Because of their role in managing internal pressures as air moves in and out of our lungs, they can even affect things like voice production, singing, and playing woodwind instruments. Singers are often taught to breathe deep down into their bellies. If a person is experiencing flatulence or incontinence problems with laughing, coughing or sneezing, these are all signs that the pelvic floor muscles are having a hard time managing the downward pressure placed on them with forceful airflow out of the body.
It's best to think of the pelvic floor muscles like a hammock that carry the weight of the bladder, and the colon. This particular hammock, however, has a release valve. If the weight it's carrying gets to be too heavy, it has the option to release some of the weight from the bowels or the bladder.
If this release happens involuntarily, we call it incontinence, leaking, or having an accident. Incontinence can happen in varying degrees. Sometimes the leakage is a couple of drops of urine, and other times it is significant enough that we need to change clothes. Bowel/fecal incontinence could include finding small stool pellets or streaking in the underwear, up to passage of a full bowel movement or having diarrhea. It can also take the form of unintended loss of gas.
Sexual Function
In regard to sexual function, the first layer of pelvic muscles have to relax to allow for penetration. If the muscles don't relax, pressing against the tightened muscles can feel forced and painful. For many people who experience "entry pain" with initial penetration during sex, the pain resolves when the muscles relax.
Women's bodies in particular often take some time to be able to relax their pelvic muscles to accommodate penetration comfortably. Increased duration of foreplay prior to penetration, tends to improve the relaxation of the muscles.
Many people are also sensitive to external life stressors. Similar to the way people develop tight and tense shoulders or clench their jaws when they are stressed, the pelvic muscles are also prone to carrying stress. Learning to relax the pelvic muscles is often part of pelvic floor physical therapy.
In terms of vaginal function, in order to experience a vaginal orgasm, the muscles surrounding the vaginal wall have to be able to rhythmically contract and relax. The first layer of pelvic muscles are a part of that lining around the vaginal wall. If a woman has difficulty with reaching an orgasm, it's possible that pain, tension and coordination problems the pelvic floor muscles are the limiting factor.
Orthopedic Function
Aside from being a gate keeper, because this layer of pelvic muscles is the most superficial, it also serves as the foundation for your back and your pelvic organs above it. For individuals with persistent lower back pain that has been unresponsive to other treatments, pelvic muscle function is sometimes the culprit.
For those who prefer a metaphorical explanation: The Leaning Tower of Pisa could not simply be fixed by moving the top floor over. To straighten out the tower and keep it from falling over, the foundation had to be addressed for it to be structurally sound.
Sadly, when talking to patients about chronic back pain, many doctors don't ask patients about pelvic health. Although many doctors are quick to comment on a person's weight as a source of their back pain, your pelvic function may actually be more important. There is a stronger correlation between low back pain and urinary incontinence than there is between low back pain and BMI (body mass index).
Interestingly, there is also a stronger correlation between allergies and low back pain than low back pain and BMI. Because of the role that the pelvic floor muscles play in managing air pressure, pelvic floor treatment often involves conversations about breathing. (Coming soon, See: Breathing: Why Laughter Really is Medicine)
Closing Thoughts
Pelvic health is often an under-discussed topic. Many people, even doctors, feel uncomfortable discussing it. It's important to recognize, however, that pelvic floor problems are incredibly common. It's estimated that urinary incontinence affects approximately 60% of adult women (1). Pain during sexual intercourse, also called dyspareunia, is believed to affect 10-20% of women (2), and is likely under-reported. 1 in 12 adults (8%) are estimated to have fecal incontinence (3)
While this article is intended for educational purposes, it should be a conversation starter, and is not a replacement for individual medical advice from a licensed healthcare provider. If you are interested in advice for your unique situation, click to book online and schedule an evaluation appointment with a pelvic floor physical therapist. If you don't live in our area and need help finding a provider, the national provider directory for pelvic floor physical therapists can be found here.
References
(1) Updated Prevalence of Urinary Incontinence in Women: 2015-2018 National Population-Based Survey Data - PubMed (nih.gov)
(3) Global Prevalence of Fecal Incontinence in Community-Dwelling Adults: A Systematic Review and Meta-analysis - PubMed (nih.gov)
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