system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is actually going on when you hit your funny bone?
gpt
You're hitting the ulnar nerve, which is a big honkin' nerve that runs down your arm. Most of the time, it is cushioned beneath lots of fat and muscles, but at the elbow joint, it is exposed and relatively close to the surface of your skin. As such, it is vulnerable to impact which makes your arm feel all tingly as the impact causes it to fire off impulses.