This review of medical literature explores the complex relationship between blood flow, aging, and tendon degeneration within the human rotator cuff.

While historical studies often suggested a "critical zone" of low vascularity prone to injury, newer in-vivo research indicates that blood supply actually fluctuates based on the severity of tendon tears.

Specifically, minor damage may trigger a healthy increase in vascularity, whereas massive tears often result in a significant loss of blood flow.

The authors emphasize that exercise can boost circulation to the shoulder, offering potential benefits for physical therapy and non-surgical recovery.

Furthermore, the findings suggest that surgical techniques should prioritize preserving surrounding tissues, like the bursa, to support better postoperative healing.

Ultimately, the text highlights that genetics and nutrition likely play larger roles in shoulder health than age alone.

(Hegedus EJ, Cook C, Brennan M, Wyland D, Garrison JC, Driesner D. Vascularity and tendon pathology in the rotator cuff: a review of literature and implications for rehabilitation and surgery. Br J Sports Med [Internet]. 2010;44(12):838–47. Available from: http://dx.doi.org/10.1136/bjsm.2008.053769)