system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why a tattoo on your elbow is so painful if the skin barely has nerves there.
gpt
Your skin definitely has nerves there. In fact, the ulnar nerve that supplies the hand runs right through that area relatively close to the surface of the skin. 

It's also a major joint, and so the body will be especially sensitive to pain in that area in order to detect/minimize injury.