in man, the anatomical region that comprises the pelvic floor and is located between the apex of the coccyx posteriorly, the apex of the subpubic arch anteriorly, and the ischial tuberosities laterally.
In obstetrics, the perineum is the space between the anus and the posterior commissure of the labia majora. Its bony foundation includes the pelvic ischial tuberosities, the pubic bone, and the coccyx. The perineum also contains muscles, ligaments, fatty tissue, vessels, nerves, and some internal organs. Shaped like a rhombus, it is divided into two triangles by a line that joins the ischial tuberosities; the male urethra or the female urethra and vagina pass through the anterior urogenital triangle. The rectum passes through the posterior, or anal, triangle.
Injuries to the perineum can consist of closed or open wounds. They arise most often with fractures of the pelvic bone when there is a great displacement of fragments (indirect mechanism) or with a blow to the perineum (direct mechanism). On the average, 10 percent of all women suffer perineal ruptures during childbirth, most often with the birth of the first child. The most common diseases of the perineum are suppurative processes near the rectum upon injuries to the rectal mucosa. Surgery is required to treat injuries and suppurative diseases of the perineum.