The first of its kind, this groundbreaking book utilizes data previously obtained to research the evolution of primates and applies it to humans. Completely unique in perspective, it analyzes the anatomy of the human body and its variations and defects and explores both their medical implications and their applications in an evolutionary-developmental (evo-devo) context. It specifically addresses both muscular and skeletal birth defects in human trisomy, and contains a detailed discussion of Down syndrome, one of the most studied human syndromes.