Sue Falsone: The Normal Shoulder Joint
Where should a shoulder assessment start? Sue Falsone highlights ideal shoulder joint anatomy and identifies common issues, especially among overhead athletes.
Another thing to take note of is the SC (Sternoclavicular) and the AC (Acromioclavicular) joints. The AC joint should be sitting about one inch higher than the SC joint.
Go ahead and depress the shoulder for me.
It’s hard for her to do, but if we note the AC joint is more in alignment with the SC joint, the entire shoulder girdle is a little bit depressed. If she’s holding her shoulder blade, whether because it’s painful or if we have some weaknesses or tightnesses somewhere, and we notice that the AC joint is significantly higher than the SC joint, this gives us some information. A normal position is just about one inch higher than the SC joint.
The other thing to look at is the position of the humeral head. If we find the AC joint and then we find the position of her humeral head and put our fingers on either side of that, we can determine the position of that humeral head within the shoulder joint complex.
Ideally, this humeral head is about one-third in front of the AC joint and about two-thirds behind it. When we have somebody where the humeral head is two-thirds in front of the AC joint, we know the humeral head is sitting further anterior in the shoulder joint.
When we’re talking about an overhead athlete who needs to get some extreme external rotation in order to throw, we need to help get the humeral head back into that position.
Think about the associated arthrokinematics that go along with external rotation. In order for that to happen, the humeral head needs to roll forward. In these cases where the humeral head is already sitting way far anterior in the shoulder, where does the humeral head have to go?
There’s nowhere left for it to go, so what does it have to do? It has to blow through the labrum. It has to blow through the structure that is there to give the shoulder some stability in order to get more motion.
That’s probably one reason why we see so many asymptomatic labral tears in overhead athletes. They need to blow through the labrum in order to compensate for a postural adaptation they’ve created throughout their lives.
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