"You can just see the pelvic outlet and the ischial tuberosity, here."

It marks the lateral boundary of the pelvic outlet.

A narrow pelvic outlet indicates that the young were very small at birth and therefore pregnancy was short, as in modern marsupials.

The second theory says that synostosis begins when the foetal head gets hindered in the pelvic outlet during birth.

Anatomical differences such as the wider pelvic outlet in females may explain the skewed gender distribution.

Pelvic anatomy is also different according to gender, with a wider pelvic outlet in females.

The squatting position opens the pelvic outlet and stretches the perineum naturally, therefore making it easier to push.

Squatting is helpful during labor because it opens the pelvic outlet an extra quarter to half inch, allowing more room for the baby to descend.

The lower circumference of the lesser pelvis is very irregular; the space enclosed by it is named the inferior aperture or pelvic outlet.

Because the pelvic outlet in the female is larger than in the male, there is a greater distance between the greater trochanters in the female.

When movements in the sacrum increase the anteroposterior diameter of the pelvic outlet, movements in the sacrococcygeal joint can further increase this diameter.

The pelvic outlet or inferior pelvic aperture is the region between the subpubic angle or pubic arch, the tuberosity of the ischium and the coccyx.

Gaskin maneuver, named after Certified Professional Midwife, Ina May Gaskin, involves moving the mother to an all fours position with the back arched, widening the pelvic outlet.

Evidence for postmortem fetal extrusion may be less ambiguous when the fetal remains are found to lie within the pelvic outlet of the adult, thus indicating that partial extrusion had occurred during decomposition.

If the fetal remains are complete and in a position inferior to and in-line with the pelvic outlet, with the head oriented opposite to that of the mother (toward the foot of the coffin or grave), then there is the possibility of coffin birth.