Rotator cuff injuries occur when one or more of the four muscles and tendons of the rotator cuff (supraspinatus, infraspinatus, teres minor, and subscapularis) are damaged or strained, affecting shoulder stability and movement during activities like reaching, lifting, and throwing. They can result from repetitive overuse, trauma, or degeneration, causing discomfort and impacting shoulder function. These injuries commonly affect individuals engaged in repetitive overhead activities or sports involving frequent shoulder use, as well as those over the age of 40 due to age-related changes that make the tendons more susceptible to injury. Occupations with repetitive arm movements or heavy lifting also pose higher risk for rotator cuff injuries.