Anatomy and Function of the Male Pelvic Floor

The Male Pelvic Diaphragm

The deepest and most extensive layer of the pelvic floor muscles is found in what is called the pelvic diaphragm. These muscles as a group span the entire lower opening of the pelvis (the pelvic outlet), and consist of the Puborectalis, Pubococcygeus, Iliococcygeus and Coccygeus muscles.

The first three are collectively called the Levator Ani, and they lift the pelvic floor upward (and slightly forward) when they contract. There are 2 openings that allow passage through the pelvic floor: the urethra in front of the perineum, and the anus behind it.

The pelvic diaphragm assists the sphincters in their action as gate keepers to regulate the functions of these two openings. It also provides the primary support to the organs resting above it: the prostate, bladder, rectum, and seminal vesicles.

The pelvic floor consists of two types of muscle tissue: slow twitch (Type I), maintain a constant tone in these muscles so that the organs above them are supported and closure is maintained in the urethral and anal openings.

Fast twitch (Type II), are engaged during strong, quick contractions such as those required for intense exertion, at the end of voiding, or during ejaculation.

The Urogenital Diaphragm

Below and covering the front half of the pelvic diaphragm is a layer of muscles called the urogenital diaphragm. These muscles can be felt as a shelf beginning in the perineum and running forward to the pubic bone.

These muscles help support the pelvic floor and fix the perineal body in the midline. The perineal body consists of tendinous connective tissue and is an important central anchor point for several muscles of the pelvic floor.

The Bulbospongiosus and Ischiocavernosus muscles

The Bulbospongiosus encircles the root of the penis and connects it to the perineal body and is one of the superficial muscles of the perineum. In males it contributes to erection, the contractions of orgasm and ejaculation.

The ischiocavernosus muscle is a muscle just below the surface of the perineum, it arises by tendinous and fibers from the inner surface of the tuberosity of the ischium.

Both of these muscles help anchor and stabilize the penis and, via their role in compressing veins contribute to the initiation and maintenance of erections. The Bulbospongiosus also helps empty the urethra at the end of urination, and expels semen during ejaculation.

The role of the perineal muscles demonstrated that perineal muscular contractions are essential to full penile rigidity.

Male pelvic floor dysfunction has been associated with erectile dysfunction as well as dysfunction of ejaculation and orgasm.