Female pelvic floor skeletal muscles include levator ani muscle, caudal muscle, external anal sphincter, urethral striated sphincter and superficial perineum muscle. These muscles, ligaments and fascia form the muscular elastic system of pelvic floor. Under the coordination of nervous mechanism, they form a dynamic supporting structure, maintain the stability of pelvic organs, shape the shape and strength of organs, and perform normal functions.
In addition to the role of urination and defecation, it also provides constant support for pelvic organs. In the pelvic floor muscle group mainly composed of levator ani muscle, pubococcipital muscle is in normal tension state, which can play a supporting role, that is, it can support the uterus, ovary, bladder, fallopian tube, upper vaginal and lower rectal segments, and can prevent the occurrence of pelvic floor dysfunction diseases (PFD), such as stress urinary incontinence, uterine prolapse, rectum and bladder bulge. Pelvic floor muscles also participate in the process of sexual intercourse and play an important role in maintaining normal sexual function and ensuring sexual life satisfaction.
The pelvic floor is composed of multi-layer muscles and fascia, which supports and keeps the pelvic organs in normal position. Each muscle of pelvic floor is composed of type I fiber and type II fiber. Type I fiber is chronic and tonic contraction, long and lasting, and is not easy to fatigue; type II fiber is rapid and periodic contraction, fast and short, easy to fatigue. Type I muscle strength decline can appear vaginal relaxation, organ prolapse, sexual dysfunction, etc.; type II muscle strength decline can easily cause stress urinary incontinence, muscle atrophy and so on. In clinic, pelvic floor dysfunction is judged by measuring the muscle strength and fatigue of class I and II muscle fibers.