A word of caution for newbies doing pec injections, especially if your pec development is substandard--do not use a pin longer than 1". If you go too deep you can actually enter the chest cavity and give yourself a pneumothorax.
Gotta say again, I'm luvin' the vastus medialis (teardrop) at the lower end of the quad. I can roll up my scrub pants and do it right at my desk. About 2 weeks ago, I had just sunk my second pin balls deep into the belly (23g, 1"), and my secretary unlocked my door and came into my office. There I am, sitting behind my desk, with a pin sticking out of my quad. She asked me a question and then walked out!! She never saw it. Holy crap!! I felt like I had just been caught beatin' off!!