I also know that they work (whether they affect other areas or not) because as a student athletic trainer, one learns things that can happen and need to be fixed, when in a fight, life is much easier when you are making these things happen. general knowledge of human kinetics makes a fight a lot easier, you see the person in terms of structures instead of shapes. We are careful when we spar, as we both know anatomy and treatment that is there to prevent us from accidentally doing something really bad (as we know where the bad stuff is) and as insurance. as to saying he may end up on the floor, if you are referring to pain, he feels very little in the way of pain, the last time he experienced pain even enough to mention it was when his left leung collapsed (spontaneous neumothorax) and even then he was walking around almost like normal including wearing a backpack. in fact, most of our combined knowledge of pressure points has come from anatomy class. by knowing why something hurts, you are able to more effectively use it. BTW, the brachial artery is less anteriorthan the nerve cluster at the insertion of the pectoralis. when aiming at the second you are unlikely to hit the first.