Human fetuses evolved to slow shoulder growth for easier delivery

The growth of human shoulders slows down just before birth and speeds up thereafter; this alleviates the problem of shoulder dystocia. Computed tomography was used to obtain cross-sectional representations of the clavicle in humans, chimpanzees, and Japanese macaques; the researchers then looked at different shoulder-width to birth-risk correlations between humans and the two other primates.

from Top Health News -- ScienceDaily https://ift.tt/GpPhAoW