Beef Delivery

Paul and Larry met Paul's Mom to pick up the 1/2 beef last night. I still don't know the proper name of what to call it. Today they sorted through the different cuts and divided them up between our families. Ashlee was semi-gagging the whole time as she isn't a big beef eater, much to Paul's dismay. So many of the cuts we have never heard of. There were packages of arm roasts. Where do you think an arm roast comes from? Last time I checked a beef has 4 legs doesn't it?
-Brenda