Getting to Know Your Scapula

Ever wonder what the shoulder blades really do and how they play a role in shoulder health? The shoulder blade has various functions, but let’s talk about what it does when we raise our arm overhead. First off, the scientific name of this triangular plate of bone is the scapula. As we raise our arm overhead the scapula rotates upward at a 1:2 ratio to the shoulder joint. This means that in order to achieve a full 180 degrees of arm flexion overhead, we need 120 degrees of rotation from the shoulder joint and 60 degrees of rotation from the scapula. This is called the Scapulohumeral Rhythm.

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[Image 1] Imagine that the guy on the right is not moving properly: He’s only rotating his scapula 40 degrees and therefore has to over-rotate his shoulder joint to 140 degrees in order to get his arm above his head. Sounds like a recipe for all kinds of shoulder pain!

So what should we do to optimize our scapular movements? Let’s take a look at the key players in rotating the scapula.

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[Image 2] You can see that we have three muscles that work together to rotate the scapula: the upper trapezius, lower trapezius, and serratus anterior.

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[Image 3] The trapezius is the big, meaty muscle that runs from behind the neck all the way down to our mid back.

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[Image 4] The serratus anterior is the muscle you see on the side of you ribs that goes under the scapula and attaches to its inner edge. These guys pull simultaneously to rotate the scapula like a steering wheel.

A common pattern we see is overactive upper trapezius muscles and underactive lower trapezius and serratus anterior muscles. One sign of this includes a head-forward posture with the shoulders shrugged up, which is caused by a tight upper trapezius. If you have difficulty engaging your lower trapezius muscles, it may be a struggle to do exercises like scap pull-ups. Or, if your scapulae are winging out during plank holds or push-ups, it is a good sign that that your serratus anterior muscles are weak.

Now that we’ve gone over the basic function of the scapula, let’s talk about a few ways to improve it. A good start is to attack the muscles around the scapula with a lacrosse ball.

  1. Test your range of motion as a “before” test.
  2. Then, lie down on your back with the lacrosse ball placed against your upper trapezius muscle, arm by your side.
  3. Raise your arm straight up and back, keeping it as close to your ear as possible.
  4. Repeat this motion several times as you slowly roll the lacrosse ball all around the scapula.
  5. Once you’ve worked one scapula, sit up and retest your range of motion by raising both arms. Most likely the side that you worked on will have a better range of motion.

Try it out! We’re hoping to see more sets of healthy shoulders!

If you’re experiencing shoulder issues and want to be assessed, please feel free to email Coach Gin at or make an appointment online!

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