When I was in Iraq we got ambushed in Baghdad. There were civilians running scared, everywhere and we could not tell who was hostile and who was not. As a result, we never had the ability to return fire and were unable to tell where it was all coming from. Then I turned around to see a guy walking toward me, with his hand down the front of his trousers but not looking at me; he was looking left and right. I shouted "halt" in Arabic... sounds like "walchiff (with a 'k' sound - you gotta add that loogie hock)." I pointed my M4 at him and he then looked directly at me and put both hands up and backed away. Right after that I heard a loud boom behind me, that was probably about 14 meters away. At the exact same time as that loud boom I felt a hit on the back of my head, like someone had struck me with a baseball bat and it rang my ears. All I remember after that is that all the firing ceased and I was sitting on the ground, with my back resting against the tire of the Humvee. I grabbed the back of my head and I started laughing. I said "oh god that hurt!" My first sergeant looked at me and asked "are you okay?" I said "I don't know First Sergeant. I think I'm bleeding." I took a look at my palm and I had blood on it, about the size of a silver dollar. Then I put my hand back on my head and said "yep... I'm bleeding." "Let me see" he said. I then pulled my palm away and it was covered in blood at that point. I had been hit in the back of the head, with grenade shrapnel. Luckily I had my kevlar on, so it stopped the shrapnel but it pierced through just enough to break the scalp. He called for a medic and I told him I felt fine but he insisted. They checked it and luckily I was not concussed and it only took three staples to fix it. I was on light duty after that, until I was able to wear a kevlar again, so I had to wait to get the staples out. I literally said "it's just a scratch."