After I finished my visit, I began to walk out. The patient followed me one pace behind. The pit bull saw that I was leaving and began pulling at the chain. This time, however, the dog managed to break away from the chain. I think his leash broke at the latch. Suddenly, the dog was bearing down on me. Not really at a run, not really at a walk. My spider sense went off and I assumed a defensive stance, I guess you could characterize it as a karate stance. The pit bull came up to me and jumped slightly. I instinctively held out my left arm to fend him off while simultaneously punching at his side with my right hand. I managed to knock him down a bit, in enough time for the owner to tackle the dog, subdue and reprimand him.
Upon inspection of my left arm, I noticed three contusions - two very slight scratches that did not draw blood and one slightly deeper impression that did draw a very slight trickle of blood. It was not a puncture wound by any means but there was enough compression of the tissue around it to cause a little bit of surface bleeding. The bleeding stopped almost immediately. I even took a gauze pad to it but no blood was visible on the pad. The owner of the dog was extremely apologetic, as would be understandable in this situation. After disinfecting the wound with the items I had on hand, I sought the proper medical attention after work. I think I'll live.
I do carry with an ankle holster while at work, but there was not enough time to draw on the dog. Nor was I completely certain that it was in "attack mode" per se. In retrospect, if the dog managed to latch onto my arm I think I would do everything in my power to draw from the ankle holster and get off a point blank shot or something. I think my punch was enough to keep him from actually latching onto my arm and to give the owner enough time to get to the dog. I'm actually glad that I got off relatively unscathed.
As with any situation that results in an adrenaline-raising moment, it seemed to go very slowly but probably happened in a matter of 5-10 seconds. It was definitely something that I can catalog away in my (limited) experiences, a lesson learned. I don't intend to pursue any legal action to the owner nor the dog. I was just wondering if anyone had any input on what happened to me, and to raise awareness about, well, awareness.
I have my own critters, I am not unduly perturbed by animals, but you would think that people who call the fire department, the ems, and the cops to their house would think to round up pets. We ask the owners to get them out of the way, but sometimes little old ladies have trouble doing that. I hate to round'em up myself, cuz I don't want to get bit or have the owners get mad, but on some of our frequent flyers the dogs have gotten to know me and let me pen them up. 
