Lyn, I love the idea of "If I don't call back, I must have done a "Jack-and-Jill fell down the hill..."
My DSO tells me to always carry a cell phone if I might fall down out of sight of neighbors. But I'm bad about that.
The only time I really almost cracked my skull, a neighbor that I almost never see out of the house limped over to me (still on the ground, dazed) to make sure I was conscious. He was a better neighbor than I had known!
(I was pulling a tough weed wrapped around both hands, hunched over and "putting my back and legs into it". When the weed came out, I did a half-backwards-flip, and I am NOT athletic! Fortunately my "tuck"reflex from "look where your butt will land" training was still working, so I landed on my butt and the base of my spine, instead of whacking my skull at high speed onto an upright concrete paving stone. I think my head would have splashed like a pumpkin.)