Pelvic Floor Anatomy + Function: 101
Updated: Mar 17, 2022
Understanding the crossroads to human function.
How many times have you considered how the pelvis contributes to overall dysfunction? Some (including me) might argue that this should be considered with every client that walks into your clinic.
The pelvis is the crossroads to human function (1).
It’s time to acknowledge how integral it is to educate our clients (and ourselves) in understanding the anatomy, neurology and function of this region that could be impacting their daily routines and contributing to their pain. Let’s take a walk down memory lane and review the anatomy of the pelvis, the pelvic floor and then we will dive into its function.
Structure + Neuroanatomy
Architecturally, the pelvis is a bony basin which houses and protects our internal pelvic organs and is a connection site for numerous muscular, fascial and ligamentous structures. The term ‘pelvic floor’ identifies the compound structure which closes the bony pelvic outlet, while the term ‘pelvic floor muscles’ refers to the muscular layer of the pelvic floor (2). A heathy pelvic floor functions as a synergistic network of muscles, nerves, and connective tissues that are largely responsible for maintaining function of our bowel, bladder, and sexual systems (3). The urethra, vagina, and rectum pass through the pelvic floor and are surrounded by the pelvic floor muscles…starting to visualize how things are connected?
The pelvic floor musculature is often referred to as the pelvic bowl or the pelvic hammock by clinicians because of its shape. Try to picture a large hammock that runs from the right side to the left side of your inner pelvis and from your tailbone to your pubic bone. This hammock has a few holes in it to allow those sensitive structures to pass through: the urethra, rectum, and vagina in women and the urethra and rectum in men. This hammock is largely muscular in both sexes…yes, EVERYBODY has muscles down there…even men!
The group of muscles that comprise the pelvic floor musculature includes the following: the external anal sphincter, bulbospongiosus, ischiocavernosus, transverse perinei, sphincter urethrae, compressor urethrae, levator ani (puborectalis, pubococcygeus, and iliococcygeus), coccygeus and the obturator internus, one of the most coveted structures in the pelvis. All of these muscles, with the exception of the obturator internus, are innervated by the pudendal nerve, originating from the sacral nerve roots S2-S4. The pudendal nerve has three branches: rectal, perineal and the dorsal branch which extends to the clitoris in women and into the tip of the penis in men. This is important as dysfunction in this nerve can contribute to symptoms into one or more of its branches. (4) Now, it’s also important to understand that this isn’t the ONLY nerve that innervates these sensitive structures, we have neural redundancy into our genitalia and surrounding tissues…but more on that another time. Last, the obturator internus is innervated by the nerve to the obturator internus, originating from the sacral plexus, L5-S2 (4). Did all of the neuroanatomy chatter that take you on a trip down memory lane back to the one glorious hour of graduate school that quickly presented the pelvic floor? Welcome back, my friends…welcome back.
Now that we have an idea of the neuroanatomy of this region…what the heck does it do?
These muscles, along with their nerves and network of connective tissues, function as part of our 'core canister’. The components of the core canister include the diaphragm up top, the pelvic floor down below and the abdominal wall and spinal musculature in the front and back. In a healthy and balanced core canister, the network of muscles, nerves, and connective tissues work together to provide optimal function of breath, postural aptitude and stability, while also maintaining proper functioning of our bladder, bowel and sexual systems (1-5). If any of these components are not working properly, it can affect the function of one or all of these systems, with or without associated pain.
While the pelvic floor itself may be overwhelming to the clinicians who don’t specialize in this area, let’s not forget how much the pelvic floor can impact the kinetic chain. The pelvis cannot be studied as an isolated structure (1). When you appreciate all of the tissues that attaches to the bony pelvis, it becomes easy to see how impactful this region is on the human body. It is our center, the crossroads of human function where the axial and appendicular skeletons intersect. The pelvis itself is our control system for force generation, load transfer and postural aptitude (1,5)…not just the muscle groups that keeps us from peeing our pants. We need to stop seeing the pelvic floor through such a narrow lens and we need to start appreciating how these structures impact day to day function from head to toe in ALL OF OUR CLIENTS.
To health + wellness for your pelvis,
1) Laslett M, Huijbregts PA, and Laslett M. Evidence-based diagnosis and treatment of the painful sacroiliac joint. J Man Manip There. 2008;16(3):142-152
2) Messelink et al. Standardization of Terminology of Pelvic Floor Muscle Function and Dysfunction: Report from the Pelvic Floor Clinical Assessment Group of the International Continence Society. Neurology and Urodynamics. 2005;24:374-380
3) Herschorn S. Female Pelvic Floor Anatomy: The Pelvic Floor, Supporting Structures and Pelvic Organs. Rev Urology. 2004;6:S2-S10
4) Raizada V and Mittal RK. Pelvic Floor Anatomy and Applied Physiology. Gastroenterol Clin North Am. 2008;37(3):493-vii
5) Rosetti SR. Functional anatomy of pelvic floor. Archivio Italiano di Urologia e Andrologia. 2016;88(1):28-37