I was surprised to see this thread had not trickled away. I must say, quite entertaining. I guess my writing was less expository and more a self examination of how I ended flat on my back next to my bike with a goodly scuff on the back of my helmet. So the long and short of it is, I fell. I try not to fall a lot. I have RA in my hands, wrists, knees and feet. All the toes on my left foot are dislocated. I carry a cane strapped to my saddle bag. Mounting and dismounting my ride always involves a bit of pain and a carefully choreographed sequence of incremental movements. That day in Homedale, feeling adventurous after a couple gin and tonics in Marsing, I broke my routine, and fell.
Took about a month for my knee to reduce to it's normal creaky self.