Why "hand" for direction?

Moderator Note

Note that while the word “retarded” was once a perfectly acceptable medical term, these days the word is considered to be both outdated and offensive. Please avoid using it here on the SDMB.

ETA:

Moderator Warning

After review, we have determined that an official warning for personal insults is also necessary. Do not insult or attack other users outside of the Pit.

Also, many of your posts in this thread are hostile to users who are merely responding to your questions. This behavior is also inappropriate outside of the Pit.