Are there things you assume you know? Probably lots of stuff.
I emailed a doctor I know about a lower back problem my Mom has, describing it as the spinal cord being impinged around the lumbar spine at vertebra L4 or L5.
Here’s part of the doctor’s response, “… actually there’s no spinal cord at that level. The cord usually ends around T12 or L1 (occasionally down to L2). Below this point are just the nerve roots that travel down to their respective exiting foramina. So it’s just a bunch of nerve roots hanging down and this is called the “caudal equina” or horse tail…”
Up until reading this I’d envisioned a spinal cord traveling down the entire length of the spinal column from the brain down to the tailbone with nerves exiting at various points from each vertebra where needed. Wrong, it ends in a horse tail configuration; it’s not just a gradually tapering cord down ending in the tail bone.
You don’t know what you don’t know. And it’s sometimes interesting to find out new or better information that clears up a blind spot you didn’t know was there.