Foreshortening

Foreshortening

Foreshortening is basically an optical illusion created from a compressed looking drawing in perspective. This perspective is distorted in order to create a false sense of depth, and is used a lot in comics – Like Superman flying with his outstretched arm coming out of the page, or a fist connecting with a villain’s face, etc. These drawings you see that appear to come off the page use some form of foreshortening to create that illusion.

Note how the size of the hands get bigger as they get closer and the arms get smaller. 

Here is a another simple tutorial by Gene Kelly: