Can you hit a blood vessel on your elbow by hitting it on something?

Not: Blood vessels are well protected in the elbow. The ulnar nerve can be felt but no blood vessels.

Yes.: If you bang your elbow hard enough you will end up with a swollen elbow that becomes bruised (black and blue). The swelling is from the tissue trauma and the black and blue is from bleeding under the skin from usually a ruptured vein. Over several days the blood from the vein rises to the surface and is seen under the skin only then to resolve over several days.