You know how I've had problems with patterns being too big in center front and center back, at least at my current weight, and so I thought that my shoulders were too narrow? I think I finally understand what's going on, and it isn't that my shoulders are narrow - it's that my bust is big.
There are two bust area measurements that can be taken: the bust itself, where the tape measure goes over the fullest part of the bust and stays parallel to the floor all around; and the high bust, where the tape measure is in the same place as the bust in the back but is raised in front to go above the bust fullness. A bust measurement no more than 3" larger than the high bust indicates a B cup while a bust measurement more than 3" larger than the high bust indicates a C or larger cup.
Most people can use the bust as a guide in choosing the pattern size because most people will be about a B cup. If someone has a C or larger cup and chooses a top or dress pattern according to the bust size, the bust will fit properly but the shoulders and armholes will be way too big. So the solution for those with a C or larger cup is to choose the top or dress pattern size based on the high bust measurement and then make a Full Bust Adjustment (FBA) for the bust. This means that the shoulders, chest, and bust will all fit properly. I should mention here that making an FBA is way easier than grading the shoulder area down :).
Note: I suspect, although I'm not sure, that if the bust and high bust measurements differ by less than about 1" this indicates an A or smaller cup. Those with an A or smaller cup could use either measurement to choose the top or dress pattern and then make a Small Bust Adjustment (SBA) to fit the pattern to them.
Anyways..... it turns out that right now, my high bust measurement is about 4" smaller than my bust measurement. I guess I'm not the B cup I thought I was :) I've been choosing my pattern size by my bust measurement when I should be using the high bust measurement! No wonder I was having fit issues through the shoulder and armscye.
I'm pretty sure that I knew about all of this - I definitely remember reading about how to select a different pattern size based on the high bust measurement and all that - but I never thought that it applied to me. I guess the difference between my bust and high bust is more pronounced right now because I'm carrying some extra pounds.
Speaking of extra weight, the other day I told my oncologist that I wanted to lose some of it. She said, "Why? What's wrong with your weight now?" I could have kissed her - who doesn't want a license to be chubby? :)