This article is definitely worth a read if you are pregnant and preparing for labor. And especially if you are interested in anatomy! According to the article, it may be particularly applicable if any of the following are present:
A long and difficult labor in which normal remedies (Rebozo Sifting, Position Changes, Spinning Babies Maneuvers) are not fully effective
Persistently malpositioned baby
Highly athletic mother (especially those who are highly athletic into their pregnancy)
History of any trauma in which the ligaments of the pelvis could have been affected (accidents, falls, etc.)
A visible Pelvic Upslip: One (usually left) iliac crest superior to the other, one leg (usually left) functionally shorter than the other.