The astute clinician benefits from a sound understanding of normal pelvic floor physiology. This article provides a framework for the material that follows in this issue.

The female pelvic floor includes all of the tissues between the pelvic peritoneum and the perineum, the myofascial elements of the pelvic diaphragm, the bladder and urethra, the uterus and vagina, and the anorectum. Optimal urinary and colorectal storage and elimination depend on complex structural and functional integrity of the pelvic floor.

The pelvic diaphragm, a musculotendinous funnel, serves as the principal support of the pelvic viscera as well as partition between the pelvic cavity and the perineum. The pelvic diaphragm surrounds and is pierced by the urethra, vagina, and rectum. The principal muscles in this group are the levator ani and coccygeus.<sup>16 DeLancey J.O.L. Functional anatomy of the female pelvis Female Urology Philadelphia: JB Lippincott (1994).  3-16

Cliccare qui per andare alla sezione Riferimenti, 45 Netter F.H. Normal anatomy of the female genital tract and its functional relationships The CIBA Collection of Medical Illustrations, vol II. The Reproductive System New York: CIBA-GEIGY Medical Education and Communications (1965).  89-123

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Physiologically, the muscles of the pelvic floor differ from most other skeletal muscles in that they demonstrate constant electrophysiologic activity except during voiding, defecation, and the Valsalva maneuver. This property enables them to maintain tone even during times of rest, providing primary support to the pelvic contents. When voluntarily contracted, the muscles of the levator ani pull the pelvic organs anteriorly against the pubic bone, constricting the pelvic organs closed. By definition, the levators elevate the anus anteriorly, forming the anorectal angle that is critical in maintaining fecal continence. The levator ani has a dual innervation with the pelvic surface, receiving direct somatic efferents from the pelvic nerve (S2-S4). The perineal surface is innervated by the pudendal nerve (S2-S4) (Figure 1).<sup>39 Laurberg S., Swash M. Effects of aging on the anorectal sphincters and their innervation Dis Colon Rectum 1989 ;  32 : 737-742  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 40 Lee S.J., Meagher A.P., Pemberton J.H. Structure and function of the lower gastrointestinal tract The Female Pelvic Floor: Disorders of Function and Support Philadelphia: FA Davis (1996).  22-32

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