Bill Hartman 7:27–10:16
Okay, so that would be a restriction of internal rotation of the shoulder if the sternum is pushed down. Do this for me. Put your arm up in like a 90 degree angle there. Perfect. Now, don't change the shoulder orientation, just bend backwards. Did your hand go back too? Yes. So does that make it look like there's more external rotation? Yes. Okay. Was it more external rotation in the shoulder? Not relative. No, that is correct. Okay. So, when you see a magnification, your ER in your shoulder and your hip should match, which means you should know already before you even measure somebody. Unless there's a constraint problem, like a torn labrum, then the rules change. But when you're measuring somebody, if you measure an ER, you should have a similar limitation in ER in the opposite extremity. It looks like you don't. It looks like you have a lot of ER, especially on one side. But the reality is, if you're anteriorly oriented and you're laying on a table, the table becomes a constraint. So if you lay on the table and roll backwards as many people do, you don't see the restriction of ER in the table measure. The magnification tells us that chances are you lay backwards on the table, assuming all constraints are intact. There are situations where you'll have outlier measures, like cricket bowlers and baseball pitchers, who have a lot of rollback on the table, giving them a truly magnified ER representation. They get twists in the bones that magnify the ER. Typically, what you're looking at is a layback on the table, and if we saw more on the right, that's because the left side of your body is probably not touching the table relative to the right side. You're kind of measuring like this.
shoulder external rotationmeasurement artifactbody position effectsmagnificationconstraint