system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does numbness work? Why is it so hard to move a body part that's numb?
gpt
Numbness isn’t always tied to lack of blood flow like has been described. A nerve itself can be compressed or pinched or otherwise impaired so that signals can’t properly be sent. Like if you slip a disc in your back and a nerve is pinched. Or if you get inflammation in your wrist from overuse and the swelling puts pressure on the nerve.