What is characteristic of Stage I impingement?

Stage I impingement, often referred to as "edema and hemorrhage," typically presents with intermittent mild pain during overhead activities. This stage reflects an early inflammatory response due to mechanical irritation of the rotator cuff tendons and the surrounding soft tissues as they pass through the subacromial space.

Patients in this stage usually experience discomfort that can be exacerbated by specific movements, particularly overhead motions, but the pain is not constant or severe. The intermittent nature of the pain means that it is not felt at rest and tends to occur primarily during active use of the shoulder, making it a significant characteristic of this stage.

In contrast, Stage II impingement would show more persistent symptoms, and Stage III might involve more severe pain at rest and significant functional impairment, indicating a progression of the condition. This distinction is key in understanding the different stages of shoulder impingement and the treatment approach required for each.