Measurements for knitters

"Our bodies go inside the schematic."
I love this language from Lily (creator of the Untangled Knitting Podcast). The knitting world generally recommends a size based on full-bust measurement, and yes, we need our busts to go inside the schematic. But today I want to establish some other measurements because y'all, your WHOLE BODY needs to go inside the schematic.
And I hear some GREAT questions from knitters who are trying to take their measurements but get stumped.
"Which shoulder bone?"
"Is that around, or straight down?"
"Which measurements really matter for knitting?"
How to take your measurements for knitting

Upper chest
Wrap tape flat across your shoulder blades, under your arms, and across your chest immediately under your arms (above breasts, if you've got 'em).
Full bust (sometimes just called bust)
Wrap tape around the fullest part of your chest, parallel to the floor. This is NOT your bra size (that's based on your underbust!).
Bicep & wrist
Wrap tape around the fullest part of your arm, with arm down at your side, keeping tape parallel to the floor. Go ahead and do this for your wrist, too.