The evolution of human anatomy and locomotion

The interplay between anatomy and evolution has been at the heart of the American Association of Anatomists since its origin in 1888 with its first president, Joseph Leidy, who was a paleontologist, biologist and anatomist. Our current conception of the basic trajectory of human evolution is even younger, dating back only to the 1925 discovery of Australopithecus . Since then, an impressive array of hominin fossils have been discovered, resulting in a more complex and nuanced view of how humans evolved than Leidy could have imagined. These fossils show us that the transition to upright, bipedal locomotion is the hallmark of the human lineage, and that the specialized anatomy associated with bipedality was present in our earliest ancestors. An appreciation of the functional demands on the human skeleton imposed by upright posture, and the resulting anatomy and variation that remains within humans, is at the forefront of medicine and contributing to advances in management and treatment of modern human disorders. Reviewing some of the most recent hominin fossil discoveries highlights that it is consideration of human and comparative anatomy that informs our interpretations of these fossils, but also that understanding the sequence of morphological changes that shaped our lineage gives us important new perspectives on modern human anatomy, function and dysfunction.