Far more likely to be tape actually ;)
I imagine the hand is done in the conventional way which is from the tip of the thumb to either the tip of the pinky or tip of the ring finger. I've seen both used but the pinky is the norm(I measure better on the ring, not sure if thats the norm or not). Not sure on arm, can be done in many ways. Most normal would be from armpit to either tip of middle finger or wrist. That will be shorter than if you do top of shoulder to whichever. Can also do a wingspan and then discount the body width. I know the NBA uses wingspan, which is standing with both arms out, tape from middle to middle.