MALE BONES ARE BIGGER AND STRONGER, in both size and density. Peak male bone mass is around 50% more than women’s, and women lose bone faster as we age. Black people have significantly stronger bones than whites: black women’s peak bone mass is the same as white men’s.
WOMEN AND MEN HAVE THE SAME NUMBER OF RIBS. We have 12 pairs, though some people are born with 11 or 13 pairs to no ill effect.
MEN HAVE BIGGER HEADS AND LONGER ARMS AND LEGS than women, relative to body size. Sources differ on comparative limb length but they all agree women have smaller, lighter heads & necks. Did you know a human head weighs about 5kg?
The biological sex of an adult skeleton can be determined with 95% accuracy by measuring the hip bones alone, 83% accuracy by the skull, and 80% accuracy by the long bones (femur & tibia).
WOMENS ELBOWS AND SHOULDERS are slightly different from men’s. Our arms bend a little further from our bodies and are more mobile at both joints.
FINGER LENGTH: Greater exposure to androgens in utero leads to a 4th (ring) finger that is longer than the 2nd (index), as often seen in men.
WOMEN HAVE A LONGER TORSO. Our skeleton accommodates extra reproductive organs and finds space to push things out of the way during pregnancy. It makes our legs shorter than men’s.
THE LARGER FEMALE PELVIS is better adapted for childbirth. It’s wider, longer, and held together by ligaments that soften during pregnancy, allowing the two halves to slide apart because of their narrow pelvis. Women’s slanted thigh bones put extra pressure on the knee joints, which have to rotate while men’s do not.
MEN HAVE BIGGER BRAINS by more than 10% relative to body size. Women’s brains have more connections between the two hemispheres, using both sides of the brain much more often than men.
