Humerus of Edmontosaurus annectens
The humerus is the long bone of the upper arm (front foot). We do not know how much time hadrosaurs spent walking on all four feet and how much time they spent walking on their much larger and very substantial rear legs. In any case, the smaller front legs appear capable of bearing weight, but do not appear to have been designed for active walking or running. The humerus shown, being excavated from the Cretaceous sediments is typical of those found with skeletal remains of Edmontosaurus annectens. It is 60 cm long (24 inches). The same bone in your body is about 10 inches long.