Data point: In High School a friend fell off a 2nd story apartment balcony railing onto sidewalk concrete. She’d been sitting on the railing & went over backwards. ~12 feet from railing to surface.
She landed in about a 45-degree head down/feet up attitude. Her head hit basically on the corner where the face joins the left side of her head.
Result: 6 months in hospital/rehab, drop of ~40 IQ points, personality went from vivacious to coach potato. Despite major use of modern (well, 1970s) medicine/surgery, her face was obviously crooked & her left eye didn’t track right but still saw OK. She had no paralysis, but did have some awkward movements, like after a minor stroke.
Another couple of feet or a more vertical impact would probably have broken her neck in addition to the above.
Imagine a shuffling, not-quite-right checkstand operator at a cow-county KMart & you’ve got the idea. Before the fall she was in athletics, the band, got good grades & was popular, attractive, & seemed likely to do real well in college.
Damn, that was a shame. I hadn’t thought about the accident for probably 10 years. We weren’t real close, she was mostly just another girl in my graduating class. I wonder how she ended up?