The largest muscle in the human body is the Gluteus Maximus. It is responsible for keeping your posture upright, and is the principal antigravity force working when you walk up stairs.

"BODY WORLDS: The Anatomy of Happiness," which made its North American museum debut at the Science Museum of Virginia, runs through Sept. 2.

A Manual of Practical Anatomy: A Guide to the Dissection of the Human Body. Prof. Thomas Walmsley By. In 3 parts. Part 3: The Head and Neck. Pp. viii + 272.