Allan,
Mark's stress analysis is right on. The stresses aren't in the direction to be of concern to the keel. Beyond that the strength of this type of alloy known as a "super alloy" in the world of jet and rocket engines is so strong your bones will give way long before the prodisc.
Here's some dicey info on retro vs spondo (I'll let Mark comment or delete if it's too off the mark). I always thought a mild spondo condition could often be associated with par defect. A more severe spondolis... could be associated with fractures as seen in the figures and x-rays in the spineuniverse article. Slight retro is good in that (i would think) it means you don't have notable bone defects. As a disc collapses the facets will guide a healthy upper vertebral body slightly backward relative to the lower body. I've tried to explain this observation to a few people but Laura (annapurna) is the only person who ever understood immediately what I was talking about.
changing the subject now, We're in our 4th night with no electricity and 20 deg temps here in the northwest. I'm at work just to stay warm and have internet. It's mostly dark if you drive at night. Gas stations with power to pump are out of gas. It's turning into a mad max movie.
see ya,
Jim
|