Originally Posted by Todd Gastaldo
The sacrum is a single bone comprised of five sacral vertebrae that are
normally fused. (The coccyx - or tailbone - is a much smaller single bone -
at the very end of your spine comprised of three to five tiny coccygeal
vertebrae that are fused.)
Sounds like you are aware that you have a "lumbarization"
of your first sacral vertebra (S1) - meaning that the
first sacral segment - which is usally fused to the rest of the sacrum -
instead *articulates* with the rest of the sacrum - like the last lumbar
vertebra does - hence the "6th lumbar vertebra" phrase - but I'm pretty sure
that 6th "lumbar" vertebra is a sacral vertebra - so they call it a "sacral
lumbarization." (Phew! Long sentence - sorry!)
I read the material quoted above, and felt compelled to create an account just to comment.
The 6th LUMBAR vertebra, as the word lumbar would suggest, is not an outlier of the sacrum nor is it in any way related to the coccyx. It's a recessive genetic trait, particular to certain Anglo/Northern European groups. With no difference in the sacrum, there is simply an extra lumbar vertebra. The vertebra is sometimes subject to "sacralization," or fusing with the sacrum over time, but that can happen to anyone, 5 or 6 lumbar vertebra, regardless. Whoever posted the quoted information above, ought to have their credibility examined.