A man's and a woman's pelvis
The pelvis differs more between men and women than any other part of the skeleton. This model's pelvis is a man's. Its bones are heavy, and its inlet, the ring at the brim seen here from above, is narrow and heart-shaped.
A man's pelvis from the front, Gray's Anatomy, 1918, figure 241Wikimedia Commons, Henry Vandyke Carter, Public domain (Gray241.png)
A woman's pelvis is wider and shallower, with lighter bones. The inlet is round or oval and wider from side to side. The angle under the pubic symphysis is about 80 to 85 degrees against 50 to 60 in a man, and the sacrum is shorter and broader. These differences give a baby's head room to pass at birth.
A woman's pelvis from the front, wider, with a rounder brim and a wider pubic arch, Gray's Anatomy, 1918, figure 242Wikimedia Commons, Henry Vandyke Carter, Public domain (Gray242.png)
Because the differences are so clear, the pelvis is the part of a skeleton that forensic scientists look at first to tell its sex.
Sources
- Susan Standring (ed.), Gray's Anatomy, 42nd ed. (2020), chapter on the bony pelvis and lower back.
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