When it comes to bleeding, what you can't see can be more serious than what you can see. Visible bleeding from a broken nail or cut ear looks scary and makes a terrible mess, but internal bleeding in the chest or abdomen that you can't see is much more dangerous.
The tail is an important part of the feline anatomy and is actually an extension of the spine. The wagging tail is a communication tool in the feline world, so a cat that doesn't wag his tail is an indication that something might be wrong. Common tail injuries in the cat include abrasions, lacerations, fractured tail, and nerve damage.