The pelvic floor is the group of muscles that reside in the bowl of the pelvis. The most traditional naming of the pelvic floor muscles is "levator ani," which, as you may guess, literally means "lifting the anus." There are 3 muscles on the right and left that comprise the levator ani: pubococcygeus, iliococcygeus, and puborectalis.
What is the pelvic floor's job?
1. Core/pelvic organ support: (see core post) The pelvic floor is a critical piece of the core, and in high demands of the other core muscles it, ideally, is also contracting in response to the demand placed on it. The pelvic organs live just above this layer of muscles. The pelvic floor supports them and does not let them fall out!
2. Continence: The pelvic floor is responsible for closing off some critical openings in your pelvis, which include the urethra (urine's exit) and the anus/rectum (bowel's exit). The pelvic floor has a resting tension (even at rest!) that maintains closure of these exits. When there is an increase in demand (think: cough, sneeze, laugh, jump, run, etc.) the pelvic floor has to increase its force to maintain closure of these openings to prevent leakage.
3. Elimination: The pelvic floor is also responsible for allowing the exits to open. Thus, it is a relaxation of your pelvic floor that allows you to urinate and defecate. It is also a profound relaxation and stretch that is required for vaginal delivery of a baby!
4. Sexual function: The pelvic floor responds during arousal and is the muscle group providing the muscular contraction of an orgasm! It is also worth saying that in order to participate in any form of penetration, the pelvic floor needs to be accommodating or flexible enough to allow for any object or body part being inserted.
5. Breathing: Perhaps the least known function is the role that the pelvic floor plays in breathing. Every muscle has an opposing muscle: the is often called an antagonist muscle. The antagonist muscle of the pelvic floor is the respiratory diaphragm. Thus, when the diaphragm is contracting (you are breathing in) the pelvic floor is relaxing. When the diaphragm is relaxing (you are breathing out or exhaling) the pelvic floor is returning to its resting level of tension. For me, the easiest way to remember this relationship is to consider sneezing and coughing: these are forceful exhalations and they require strong support from the pelvic floor to maintain continence, to keep from leaking!