I'll try and keep this short. I was shredding an area I've done dozens of times before, crawling around in low gear.
Next thing I can remember is being doubled over still sitting in the seat, motor running, tractor not moving. Reached around shut the motor off. Hobbled to the house, called a neighbor and he drove me about 54 miles to the hospital. They inserted a chest tube for the collapsed lung the then off to the trama center in San Antonio. No bruised or broken ribs, fractured left fibula, hole the size of half dollar in the left leg, about 75% of the skin scrapped off my left arm.
Looking back, it looks like limb caught the left tire and the tractor spun around somehow bringing the about 6" limb around, came down, hit my back pinning me down continued down, bent the steering whee, then hit the clutch pedal, broke it off and kept the pedal depressed thus throwing it out of gear and kept the shredder from running.
Things happen fast, again I have no idea how it happened, and the rehab on this 80 year old body is going to take a while.