The knobby protrusion at the base of the back of your neck when you lean your head forward. It's used for backpack sizing.
C7 is important.
You need it.
C7 means that it's the seventh (last, bottom) cervical (neck) vertebra. C7 is part of your neck bone, which is connected to your head bone and connected to your back bone and used to measure you for a pack bone. Memorize that.
Anatomists like to number similar things, which is why C7 is C7 and not Louise. (Glad we cleared that up too.)
Anyway, the vertebrae in your neck are like all the rest of them in your whole spinal column. (Because the Lazy Principle. Once you got a thing what works, keep using it, 'K? Then you can take more naps and do less fretting. Fretting is for amateurs and noobs. Laziness is for professionals. Whoever designed the human body is obviously a lazy bastard professional, as you probably know by now.)
So these bony vertebrae things help keep your various body parts together and allow you to stand up on your hind legs with your head held smartly in line as all the other self-respecting tailless apes do. It's a thing, a handy one, a handy thing. And people point and laugh less when you do it like this too.
These vertebrae provide a nice home for your spinal cord while giving various bodily muscles handy places to attach themselves.
Two things about C7 are especially important.
The first is that it works with the other vertebrae in your neck to keep your head attached, of course, as you should know by now, and the other is that the knobby protrusion at its back (the "dorsal process", a place where your muscles grab hold) is a handy landmark for measuring what size pack you need. See?
Measure from C7 down to the top of your pelvis and compare to the manufacturer's chart for the pack you're eyeballing. It's easy from there on out if you're not exceptionally stupid. You're not, are you? (Please see the next paragraph to be sure.)
Note: "C7" is not the same as "C4", which is a plastic explosive and not part of your body, and should not be taken internally and tastes bad too.
That's about it. Time for my nap.
Have anything worth adding? Then try sosayseff@gmail.com
Me? No — the taste of C4 is not getting any better, even with strawberry jam.
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