Mednikova and her colleagues believe that “compared to anatomically modern humans, (both male and female Neanderthals) had a larger muscle mass and experienced a higher loading on the upper extremity than did Homo sapiens.” Also, “they differed from modern humans by a greater functional difference between the sexes in the use of the right arm.”
Neanderthal males had Popeye-type right arms, while Neanderthal females had arms that were more evenly matched and not nearly as muscular.
Mednikova and her team analyzed a fossil humerus (long bone that extends from the shoulder to the elbow) for what they believe was an Neanderthal male that might have lived around 100,000 years ago in what is now Khvalynsk, Russia. The bone was put through computerized tomography, X-rays and other analysis.
The fossil displays an unusual mixture of thickened walls with narrow bone marrow region cavities. This, according to the scientists, suggests “intense mineralization” provided for the strong, sturdy bone structure, with the inner narrowness “based on a stronger shaft architecture requiring much less mineralization.”