Now "Dismemberment" to me isn't a rule or a principle or even a habit but more of a simple reminder that you ain't restricted to reality with cartoons. This is a strong side of cartoons purely in general which is odd that we don't see it being used that much nowadays.
Here's a famous scene from one of Tex Avery's most famous cartoons (I think) "Red Hot Riding Hood". If you've seen "The Mask" then you've seen this scene.
Now in this scene you'll notice if you slow it down really slowly, you'll notice "Dismemberment" in action.
This is where is it kicks into action, it's only a quick anticipation part and part of him is off scene but it's there. The head is unnaturally pointing up while the body is merely slightly twisted. Now you may not think much about this but it's technically impossible for a "normal" person to twist into this pose.
I've tried it myself.