The true pelvis, also known as the minor or lesser pelvis, consists of structures comprising the wall, space and contents and is bounded by, and includes: superiorly the superior pelvic aperture; inferiorly the inferior aperture of true pelvis and pelvic diaphragm; and laterally the skeletal pelvic wall comprised of the bones, joints, ligaments of the pelvis and associated muscles (piriformis and obturator internus). The content includes the urinary bladder, sigmoid colon (although it is acknowledged that this is mobile and sits in a variable location), rectum, anal canal, pelvic segment of ureter and the retropubic and presacral space; the female pelvis also includes the ovaries, fallopian tubes, uterus, vagina, female urethra, soft tissues including the broad ligament and the retrouterine pouch of Douglas; the male true pelvis also contains the prostate, male urethra, seminal vesicles, soft tissues including the pubovesical and puboprostatic ligaments and the retrovesical space.