Many types of manual labor require you to perform repetitive motions of your arms. This can put you at risk of developing repetitive stress injuries of the upper extremities. Although RSIs qualify for workers’ compensation, it can be difficult to prove that they resulted from work activities. Therefore, it is common for insurance companies to initially deny them. 

The shoulder joint is a point vulnerable to stress from repetitive motion as well as trauma. Work-related injuries at the shoulder are likely to affect the rotator cuff. 

Rotator cuff muscles 

The rotator cuff consists of four muscles that move and stabilize the shoulder: 

  • Teres minor: The smallest of the four, it functions to rotate the arm away from the body 
  • Subscapularis: Connects your upper arm to your shoulder blade and allows you to raise and lower your arm 
  • Infraspinatus: Aids in shoulder extension and rotation 
  • Supraspinatus: Helps you lift your arm while keeping your humerus stable 

Common rotator cuff injuries 

Your rotator cuff provides you with a remarkable range of motion of your shoulder, but this flexibility also makes the muscles and supportive structures more susceptible to injury. 

1. Rotator cuff tear 

The muscles of the rotator cuff can become torn completely, which is a full-thickness tear, or they can fray, which is a partial-thickness tear. Rotator cuff tears can happen acutely due to sudden trauma. However, they more often develop over time due to wear and tear on the muscles. 

2. Bursitis 

A bursa is a fluid-filled sac in the shoulder that serves to cushion and protect other structures. Repetitive motion in the shoulder can cause the bursa to become irritated, and bursitis results. 

3. Tendinitis 

The tendons are strong bands of tissue that connect the muscles of the rotator cuff to the bones of your shoulder joint. Irritation or inflammation of the tendons can result from repetitive motion. 

If you suspect a work-related injury to your rotator cuff, whether due to repetitive motion or sudden trauma, you should report it to your employer and see a doctor right away.