The Rotator Cuff

Have you ever been told that you’ve had a rotator cuff injury or perhaps had a tightness or pain in the shoulder? We are going to break down exactly what the rotator cuff is and what role it plays in keeping our shoulder functional and pain free. 



What is the Rotator Cuff? 
The rotator cuff is a group of muscles that help keep your upper arm bone (the Humerus) secure within the shoulder socket. There are 4 muscles that do this job for us and each play its own important role, Supraspinatus, Infraspinatus, Subscapularis and Teres Minor. 

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• Supraspinatus: Is the smallest of the four muscles in the rotator cuff and it attaches to the top of the shoulder blade and the top of the Humerus. It initiates shoulder abduction that moves the arm sideways, away from the body. 
• Infraspinatus: Is a thick triangular muscle that attaches to the back side of the shoulder blade and the Humerus. It helps to move the arm backwards and outwardly rotate it into external rotation of the shoulder.
• Teres Minor: Is a long thin muscle that sits underneath infraspinatus and attaches to the back side of the shoulder blade and Humerus. It assists in moving the arm out to the side away from the body and bringing the arm backwards. It also helps to outwardly rotate the arm into external rotation. 
• Subscapularis: Is a large triangular muscle that sits on the underside of the shoulder blade. It helps to move the arm sideways away from the body and inwardly rotate the arm to produce internal shoulder rotation. 

Why are injuries common to the rotator cuff? 
As we use our shoulder so frequently during day to day movements it can often suffer from some wear and tear. This wear and tear is increased if you have a job that requires frequent movement of the arm in a repetitive motion, play sports that require a high degree of shoulder strength or are constantly lifting heavy loads or working overhead for long periods of time. 

As the shoulder can move through such a large range of movement (forward, backwards, side to side and overhead) these 4 muscles have a large role to play in the stability of the shoulder joint. When one of these muscles becomes injured or fatigued it can place higher stress on one of the remaining three, increasing the likelihood of developing further injuries. 

Most common injuries

• Tendinitis: Occurs when one of the tendons within the rotator cuff experiences inflammation, caused from overuse or overload. 
• Bursitis: Presents when the fluid-filled sac called the Bursa that sits between your shoulder joint and rotator cuff tendons, becomes irritated or inflamed. 
• Shoulder impingement: This occurs when the rotator cuff rubs or catches on the bones within the shoulder. It can result in persistent pain, particularly as the injured tendons begin to swell. If left untreated for prolonged periods, this can lead to rotator cuff tears. 
• Strains or tears: These can be caused when repetitive motions or abrupt movements occur in the shoulder. It can cause the tendon that connects one of the muscles to partially or fully tear. This can then cause pain, weakness in the shoulder and a limitation in shoulder range of movement.  

By Aleisha Michael 
Accredited Exercise Physiologist