Key Features 1) Detailed summary of every recorded variation and anomaly for each muscle in the human body 2) Information on comparative anatomy of each muscle (e.g., how each human muscle may appear in our closest living relatives, the apes). 3) Schematic illustrations of the variations and anomalies for easy visualization 4) Comprehensive literature review resulting in the most accurate prevalence information for each variation and anomaly 5) Diverse group of co-authors from various academic and cultural backgrounds