Role of the Rotator Cuff

Woman stretching from exercise.

Role of the Rotator Cuff

Stretching from exerciseThe rotator cuff play an important role in shoulder posture and shoulder health. There are 4 muscles that make up the rotator cuff: supraspinatus, infraspinatus, teres minor, and subscapularis. These muscles all originate on the scapula and then attach to the top of the humerus. The role of these muscles is to stabilize the scapula and the humerus during movement of the arm. Our scapula sits on our upper back and has lots of muscle attachments. There are actually no bones that attach the scapula to our body. The muscles that attach to the scapula are what hold it in place. This is why it’s important that we keep our shoulder muscles healthy. Rotator cuff injuries are very common and it’s therefore important to keep on top of your shoulder.



The 4 muscles of the rotator cuff attach on the scapula and then insert onto the upper humerus. The infraspinatus and teres minor both work to externally rotate the humerus. The supraspinatus abducts the humerus, and the subscapularis internally rotates the humerus. Although these muscles have different actions they all work to stabilize head of humerus. When the rotator cuff  are activated they provide a pulling force that brings the head of humerus into the glenoid fossa. This creates more stability for out humerus during movement. The shoulder joint is very mobile, but this comes at a cost. More mobility often equals less stability, which is why we require the muscles involved to be activating correctly.

Wear and tear

As with everything in our bodies, there is always age related changes. Due to the narrow spaces that rotator cuff tendons traverse there is often changes to the tendon morphology. This can happen at a young age. If you don’t have any shoulder pain and get an ultrasound  you will  find that you have  tendon fraying. This is very common and is not a cause for concern. However, if our shoulder posture isn’t ideal we can get pain in this area. That’s why it’s important to warm up your shoulders or have a strength program.

Correct technique

Activating the rotator cuff doesn’t require such brute force. If we have grown up with good posture and muscle activation our body will subconsciously activate the rotator cuff when we move our arm. If we have movement dysfunction then we need to relearn the correct muscle activation technique and perform strength training for the shoulder. To activate the rotator cuff sit with you arm resting on a table next to you. Ideally your arm should be at about 30 degrees of abduction. Studies show that there is the greatest EMG activity of the rotator cuff in this position. using your scapular muscles, gently try and bring your arm further into the shoulder joint. You shouldn’t be shrugging your shoulders to do this. The movement should come from your muscles on your scapula. If you can feel them working try to build up how long you can hold your arm there for.

If you have a rotator cuff injury or would like to know more, book in online or call us on 3352 5116.

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