Interesting but well-known phenomenon. When I was in training in Richmond, Va. many years ago the ambulance brought in an unconscious and unreactive middle aged woman who smelled strongly of alcohol and had an bullet entrance wound in the middle of her forehead and an exit wound in the back of her occiput. She had a "blown" pupil on one side, usually indicative of serious brain injury in this type of case, although other possibilities existed. This was before CT scans. This type of injury at that time was thought to result in death in about 4 hours, with no real likelihood of effective surgical intervention, so the neurosurgery resident put her in a holding bed in the ER with an IV running and left her there for observation until she would eventually be pronounced dead.
This was a VERY busy city ER, and while half running to X-Ray an hour or two later, I realized that I had just passed this same very drunk lady who was walking down the hall dragging her I.V. bottle, looking for the ladies loo! Turned out the bullet had hit the bony frontal boss, tracked under the scalp but over the skull and exited the back of her head...the pupilllary asymmetry was congenital. Whatever brain function she actually normally enjoyed, such as it was, was unimpaired once she sobered up. One should never assume anything in medicine but, hey, all is well that ends well!
