Rotator Cuffs – Part 6 of the grumbly muscle blog…they hug us and depress us…well, kind of…

What are rotator cuffs and what do they do?

Well, we have 4 of them on each scapula (shoulder blade). As you can imagine, four muscles, four slightly different jobs, but as a team they dynamically stabilise the head of humerus; basically they hug the head into the socket but also keep the head depressed (sitting lower) in the socket which actually gives us a better range of motion at the shoulder so as we raise our arms, allowing the head of the humerus to glide down and roll up and prevent obstruction to these movements.

They are necessary for virtually every movement of the shoulder joint. The scapula fossa (the socket, if you will) is really shallow so these muscles have a lot of work on their hands…We have.

Supraspinatus – does the first 20-30° of shoulder abduction (takes the arm away from the body).

Infraspinatus and Teres minor – both adduct the shoulder (brings the arm inwards) but also laterally rotates the shoulder.

Subscapularis – this one medially rotates the shoulder.

 

Anatomy

SupraspinatusComes from the supraspinous fossa above the spine of scapula and inserts onto the greater tubercle of the humerus.

Infraspinatus – Infraspinous fossa of the scapula and, inserts onto the greater tubercle of the humerus.

Teres Minor – Upper two thirds of the lateral border of the scapula and also inserts into the greater tubercle of the humerus.

Subscapularis – Comes from underneath the scapula (subscapular fossa) and inserts onto the lesser tubercle of the humerus.

 

Why do they hurt?

The subscapularis can become impinged (caught between two bones; the acromion process and the humerus), sub acromial pain syndrome (SAPS) is often linked to this but can include tendinopathy and bursitis. And there are often tears, particularly of infraspinatus and teres minor, the two lateral rotators.

As we age the properties of the tendon (this is the white bit of the muscle that attaches to the bone) degenerate (sorry folks, but age is a risk factor), and we can observe not only microscopic tears to the tendons and muscles and, as mentioned, tears to the muscle. Tendons can also suffer tendinopathies. I often find while I massage the rotator cuffs that they are quite tender to the touch on most people.

 

What can we do about it?

In the clinic I test for impingement using a few different tests; Empty Can test, Painful Arc (pain between 60-120 degrees is common), Hawkins Kennedy – pain in outer range can indicate impingement. Hornblower’s sign is indicative of an infraspinatus or teres minor tear. Overhead athletes are at a greater risk of rotator cuff tears.

I often prescribe strengthening of infraspinatus and teres minor as they are the main lateral rotators of the shoulder and often the weakest of the rotator cuffs when tested. However, they’re really up against it, some of the medial rotators are BIG muscles; Pectoralis major (pecs), Latissimus Dorsi (lats) and subscapularis. If you ask me its an unfair balance.  In the gym, people commonly train the pecs and the lats but don’t give due consideration to the rotator cuffs.  We need to stretch off the muscles at the front, which will improve our posture a little and strengthen the muscles that attach to and come from the shoulder blade.

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