31. Dear Gabby: The Great Shoulder Adjustment Digest — Part 2: Understanding Measurements

Hello, Sewcialist friends! Welcome to part 2 of the Great Shoulder Digest! This article is going to break down horizontal shoulder measurements, how to take them on yourself and on patterns for set-in sleeves, and most importantly, how to use them. Now that you know all about shoulder slopes, this knowledge should provide an accompaniment and make understanding shoulders even easier.

First up: let’s talk about your total shoulder width. This measurement is called “Across Shoulder Width”, and is taken from “bone to bone”. The bone in question is the outer point of the acromion, which is the uppermost and outermost point of the scapula (shoulder blade) that sits atop the humerus, or your upper arm bone.

Animated gif of black and white skeleton rotating, the acromion highlighted in red

Image is animated gif of black and white skeleton rotating, the acromion highlighted in red. Gif courtesy of wikidata.

The measurement should be taken across your back starting from one side, laying the tape on top of the muscle bulk of your shoulders, and going across to the other side. Do not take this measurement with the tape straight held away from your back- you want to be able to measure accurately how much space you’ll need inside the shoulder width of your soon-to-be-garments. If you are measuring yourself, I like to place my finger on the top of my shoulder and find the bend point when I raise my arm. You can then mark this placement with a small sticker, or a safety pin, so you can ensure your tape measure is placed correctly.

Please see the following videos for how to measure your across shoulder on both your body, and your patterns:

Video above shows Gabby giving instruction on how to easily measure your across shoulder by yourself, and where to take the measurement.
This video shows the basic principle of how to take an across shoulder measurement on an un-graded pattern. The style is a drop shoulder, however this video is only for showcasing the technique.
This video is Gabby explaining how to measure across the shoulder on three different set-in sleeves: a style with a back shoulder yoke, a style with no side seam, and a style with an over-the-shoulder yoke. The video explains how to put the pattern pieces together to measure the shoulder from center front/center back.

Why do you need these measurements, and how should you use them?

In my opinion, choosing a pattern size is hard enough! I like having the ability to choose based on your shoulder width — body circumference adjustments are easy enough to master (jump to the end of the post for some easy-to-follow resources). What’s really hard is messing with the armholes and neckline if the bust fits you but the shoulders don’t.

Now that you have both your body and pattern measurements, how do you know what will work and what won’t? If I may generalize, here’s a basic chart of what I *imagine* a good measurement range would be, based on the difference between the two measurements. This should give you an idea if the pattern size you’ve chosen will work, or if you should size up and down. Caveat — I can’t know what fabric you choose, or what pattern you have, so these are very general. Consider this a starting point for set-in sleeves. Drop shoulders will require you to use your imagination, and shaped raglans, dolmans, and grown on sleeves will be discussed in a future post.

Chart above is also linked here. Chart details difference garment types and a suggested range for a measurement difference between your pattern, and your body for a good starting point muslin.

If you end up with a shoulder width that is too small, it will pull your sleeve in towards your body, the seamline will sit inside your acromion, and you won’t be able to raise your arms straight out in front of you- the back body between your shoulder blades will appear to have horizontal pull lines between them. If you end up with a shoulder width that is too big, the shoulder seam will sit far out from your acromion, resulting in a droopy appearance with lots of folds at your underarms. Therefore, I am recommending that if the size you think you’d like to start with falls outside of the + / – range detailed in the chart, then you should consider selecting another size, for fear of ending up in a much larger or smaller size than would work using my patented ShoulderChoice method 😉

Now, with all that said, here are some go-to resources for Full and Small Bust Adjustments and grading between sizes:

Full Bust Adjustments:
Curvy Sewing Collective

Small Bust Adjustments:
Closet Core Patterns

Grading Between Sizes:
By Hand London

The next installment of The Great Shoulder Digest will touch on narrow and wide shoulder adjustments, shoulder girth, raglans / dolmans / grown on sleeves, and how it all works together to provide mobility. Look for this coming later this spring and as always, feel free to comment with questions or feedback. Thanks for reading!

Gabby is a technical designer, fit specialist, and prolific googler. She lives in Denver, raises moderately small people, reads, embroiders, makes, experiments, fails, learns, tries again. See her on instagram @ladygrift.