The best site I’ve found is. It is an interactive 3D model of the body. You can peel back different layers and select individual body parts. There is also a search feature that will highlight the body part – useful for finding muscles that are hidden behind other muscles.

You will need a browser with WebGL enabled. I think Chrome has it enabled by default. It can be enabled on Safari under the “Develop” menu. I think the Develop menu item also has it’s own enable option.