Human Anatomy Part 1 - K. A. Diubenko A. K. Kolomiitsev Y. B. Chaikovsky 2002

Special Part
Reproductive systems, systemata genitalia - Female reproductive system, systema genitale femininum
External female genitalia, organa genitalia feminina externa - Pelvic cavity - Perineum

The Perineum, or perinеum, is an anatomical region bounded anteriorly by the Pubic Symphysis, posteriorly by the apex of the coccyx, and laterally by the ischial tuberosities and sacrotuberous ligaments. When the legs are abducted and flexed, it forms a diamond-shaped area (Fig. 332) whose anterolateral boundaries are formed by the rami of the pubic and ischial bones, and posterolaterally by the sacrospinous ligaments covered by the lower edges of the gluteus maximus Muscles. Along the midline of the perineum in the sagittal plane runs the perineal raphe (raphe perinealis), which continues into the scrotal raphe in males.

The perineum forms the inferior wall of the trunk, closing the lesser pelvis from below and transmitting the Urethra, rectum, and Vagina in females. It prevents pelvic organ prolapse, contributes to urinary and fecal continence, and controls Micturition and defecation. A thorough knowledge of the TOPOGRAPHIC AND ANATOMICAL Features of the female perineum is essential when performing surgical interventions for perineal tears during childbirth.

The segment of the perineum situated between the posterior labial commissure and the anus is referred to as the perineum in the narrow sense, or the obstetric perineum.

A horizontal line divides the perineum into two regions or triangles: anterior and posterior (see Fig. 332A, B). The anterior triangle, or urogenital region (regio urogenitale), is occupied by the urogenital Diaphragm (diaphragma urogenitale), which lies in a coronal plane. It consists of a dense musculo-fascial plate comprising the deep transverse perineal Muscle and two fascial layers covering the muscle superiorly and inferiorly. Anteriorly, the diaphragm does not reach the pubic symphysis, instead forming a dense transverse perineal ligament (lig. transversum perinei). The space between this transverse ligament and the arcuate ligament of the pubic symphysis serves as a passage for the dorsal artery and vein of the Penis (or Clitoris).

The posterior triangle, or anal region (regio analis), is occupied by the pelvic diaphragm (diaphragma pelvicum), which lies horizontally. It is formed by the right and left levator ani muscles, accompanied posteriorly by the right and left coccygeus muscles and associated fasciae. The rectum passes through the pelvic diaphragm to open at the anus. Through the urogenital diaphragm, males transmit the urethra and accommodate the Scrotum and the ROOT of the penis, whereas females transmit the vagina and external genitalia.

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Fig. 332. The perineum, perineum (after Spalteholz):

A - Regions of the male perineum; B - regions of the female perineum