Abi is a beautiful, good-natured dog who got a little too close to a horse's hoof. Actually, she got kicked in the head. It turns out to be not as cool as when Dean Martin sang about it. Incredibly, she is walking around like nothing much happened.
When you look at a close-up of the cut, you might say that it doesn't look too bad, and it doesn't. What you can't see is that every time she breathes, the skin on top of her head puffs up like a balloon. She also has some bloody nasal discharge. In fact, there is a hole in her lateral frontal sinus.
Part of the skull is a double-wall construction. If the hoof impact had been farther back, it would have hit the brain-case. In this case, it broke through into the space outlined in green on this diagram. [This is from The Viscera of the Domestic Mammals. It's not computer-generated, but is old-school -- they injected the sinuses with different colors of plastic and dissolved away the bone to make this image.]
We watched Abi for a couple of hours, and she never showed any signs of central nervous system depression or shock, so we went ahead and anesthetized her for surgery. We also gave her a lot of pain medicine. Despite her chipper disposition on presentation, she has GOT to have a headache.
We had called the Veterinary Medical Teaching Hospital at the University of Missouri to ask for advice. Apparently this is a pretty uncommon injury. The resident had to call the surgeon, who had to call some other surgeons. Dr. Carol made at least four phone calls before we ever did much of anything besides monitor the dog and give pain medicine. Here is my finger showing where the hole in her skull is.
Here is one of the fragments I fished out of the sinus before we wired it all back together. Unfortunately, the top of her sinus resembled the end of Bad Leroy Brown -- it looked like a jigsaw puzzle with a couple of pieces gone. It took me about an hour to get things cleaned up, drilled, wired, and closed up.