Its a little more complicated than that. You have to have a general understanding of anatomy to make sure that you're shooting into an area without major blood vessels and nerves. First off, I'd avoid the bicep. The musculocutaneous nerve runs fairly near by, as well as the brachial artery. Don't get me wrong..a lot of people shoot there, but its riskier (you definitely DON'T WANT to hit a nerve!). If you do shoot there, flex your bicep and go for the peak. A much better area is the medial third of the lateral side of your leg (ie: divide your outer thigh into three equal regions and shoot in the middle one). This area is much safer...no major nerve roots or blood vessels to worry about. Another good area is the upper, outer portion of the glutes...no major nerves there either.
Hope this helps
V.