The pelvic outlet is found at the inferior end of the true pelvis, and it is defined as its inferior opening. The pelvic outlet marks the lower margin of the true pelvis. It is also known as the inferior pelvic aperture.

The boundaries of the pelvic outlet are formed by the coccyx, sacrotuberous ligaments, both ischium and pubis and pubic symphysis. The shape of the pelvic outlet is very irregular. However, it somewhat resembles a diamond, and its boundaries mirror the anal and urogenital triangle boundaries.

Anteriorly, the pelvic outlet is limited by the inferior margin of the pubic symphysis and inferior pubic ligament. Then, the borderline goes along the inferior aspect of the inferior pubic ramus and ischial ramus. These structures form the anterolateral limit of the pelvic outlet.

Once the borderline reaches the ischial tuberosity, it further goes along the inferior margin of the sacrotuberous ligament. The mentioned ligament forms the posterolateral limit of the outlet. Posteriorly, the pelvic outlet is bounded by the coccyx.

The pelvic outlet is transversed by the terminal portions of the vagina, rectum, and urethra. In females, the pelvic outlet supports and guides the fetus through the birth canal.

Unlock with Premium

Pelvic outlet