Well, upper bust.
I know this is going to sound strange, and perhaps I spend way too much time pondering the fit of the bust to arm, but I've been asked a bit about how to pick a sleeve when you are altering a garment, or if you want to change the sleeve on something new that you are making. Here is what I've concluded.
It all is in the boobs.
For me, when I pick a sleeve, I want one that will give me a good range of motion. To determine that, its about the upper bust/arm pit ratio and how much of you actually fills that area. Sure, we all know to adjust this when we are making a garment, but also, if you are adding a different sleeve to a garment, you will also need to take into consideration the armscye with the new sleeve.
That's why some sleeve patterns came with mockup bodice pieces to test the sleeve, which I think was brilliant. Match that up to the bodice of what you want to add the sleeve to and you're golden. But a lot of times that's not the case, and a lot of times if you are adding a sleeve, you don't take this measurements into consideration. I know I didn't. This I'm sure we all know.
