Anyone watch “Extreme Makeover” last night? Well, they had plastic surgeon modify a woman’s outrageously long nose. So the doctor says: “I took off 12 millimeters of cartilage from her nose. That’s about an inch.” Quickly doing the calculation in my head, I said aloud: “This guy’s and idiot. That’s not even a 1/2-inch.” But I thought, wait a sec, this guy’s a doctor. He can’t possibly be that stupid, especially since knowing lengths and widths is so important for his profession. I mean, imagine if a woman asks him to add 4 inches to her bust size and he adds 8? So I was hoping that someone could try to translate what he meant.
Assuming he didn’t actually say “half an inch” or “a half inch” which you misheard, then he probably just misspoke. There are, and always have been, 25.4 mm to the inch. 12 mm would be pretty close to a half an inch.
What exactly does he mean “[he] took off 12 millimeters of cartilage from her nose.”? Shouldn’t there be a unit of volume involved?
It could be measured by volume, but I think it’s safe to say that all the patient (and therefore the doctor) is thinking about is how long the nose is.
I didn’t see the program but I’d say he probably meant (or said, with you mishearing) a half inch.
A full inch seems like a lot to take off of any nose…
Sounds good to me? 
I’m with QED on this. It either was or should have been 1/2 inch. No biggie. Most Americans have no concept of metric measurements anyway.
I’m actually pretty confident he said an inch. My wife and sister both heard the same thing. Thinking further, perhaps was using the Pythagorean Theorem? If he takes away 12mm of septum, then it may yield more of a reduction to the entire length. Of course, he did say cartilage which would refer to the bridge and not the septum.