I don't quite know either, and I do like bluelakelady's take on it. All I know is my family seems plagued with spinal defects. My brother and I both have a very narrow spinal canal. We suspect the same of my sister. It doesn't take a horrific crash or much of a disc bulge or inflammation before we have serious problems. My cousin is missing half her cerebellum and she has a lymphoma in her spinal canal. Another cousin died of scleroderma at a young age. Another has all her organs backwards; i.e., her heart isn't where it ought to be. One cousin had to have braces due to scoliosis; I have scoliosis that was brought on by an accident. Another cousin was born with it. (I keep asking if there was any intermarrying going on in our family history or what the heck is the deal, but who knows--we're obviously a mess and my husband really should have checked my teeth before he married me like his grandpa said.
) Oh, and all of my siblings share my propensity to have sore throats often and to have rhinitis Oct-Mar.