Funny Signboard in Japan Metro Trains

Do you have a dirty mind? Look at picture below, can you guess the meanings of the signs?


This signboard can be found in Japanese metro trains. The signs are “Priority seats for …………….”
From left to right:
1. People with injured arm
2. People who is carrying a child
3. Pregnant woman
4. People with injured leg
OK, this is not what you thought! I know you have dirty mind, I will tell your mom!

http://funkydowntown.com/funny-signboard-in-japan-metro-trains/