Scientific Illustration

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Baby’s bony body

Newborns are a bundle of bones – more than 300 to be more precise. Over time, many of these bones fuse together. One obvious example: The 44 original, separate components of the skull, whose loose confederation allows a newborn’s head to more easily pass through the birth canal and to accommodate dramatic brain and head growth during in the first year of life outside the womb. Generally, an infant’s skull fuses together by age two to provide better protection of the brain.

Overall, the total number of bones in the body is reduced to 206 by the time humans reach adulthood.

Above is a human fetus visualized in the third trimester of pregnancy using a computed tomographic scan and volume rendering software. Courtesy of Philipp Gunz and Jean-Jacques Hublin at the Max Planck Institute for Evolutionary Anthropology in Germany.