Beckenraum

Beckenraum, or the pelvic cavity, is the space enclosed within the bony pelvis and bounded by the pelvic inlet above, the pelvic floor below, and the pelvic walls laterally and anteriorly. It forms part of the larger abdominopelvic cavity and contains the pelvic viscera, including parts of the urinary, digestive, and reproductive systems. The superior boundary is the pelvic brim (pelvic inlet), the posterior boundary is the sacrum and coccyx, and the floor is formed by the muscles of the pelvic diaphragm.

The Beckenraum is often divided into two parts: the true pelvis (kleines Becken) and the false pelvis (großes Becken). The true pelvis lies within the pelvic bones and forms the main cavity that houses the pelvic organs; the false pelvis is the upper, funnel-shaped portion situated above the pelvic inlet and largely part of the lower abdomen. The two parts are separated by the pelvic brim. The peritoneum covers portions of the pelvic organs and creates potential spaces, such as the rectouterine pouch (pouch of Douglas) in females and the rectovesical pouch in males.

Contents of the pelvic cavity include the urinary bladder (when distended), the rectum, and the reproductive organs: uterus, ovaries, and fallopian tubes in females; prostate and seminal vesicles in males. Ureters pass through the pelvic cavity on their way to the bladder. The pelvic viscera are supported by ligaments and the pelvic diaphragm, and they receive blood supply from branches of the internal iliac arteries, with corresponding venous drainage to the internal iliac veins. Innervation is provided by autonomic plexuses and somatic nerves such as the pudendal nerve, with lymphatic drainage to the pelvic nodes.

Clinically, the Beckenraum is a focus in obstetrics, urology, gynecology, and colorectal surgery, and is involved in conditions ranging from pelvic fractures to tumors and inflammatory diseases.