Orthopedics Sports Injuries Tendonitis Watershed Zone of Tendon By Jonathan Cluett, MD twitter linkedin Jonathan Cluett, MD, is a board-certified orthopedic surgeon with subspecialty training in sports medicine and arthroscopic surgery. Learn about our editorial process Jonathan Cluett, MD Medically reviewed by Medically reviewed by Eva Umoh Asomugha, M.D. on November 13, 2020 linkedin Eva Umoh Asomugha, MD, is a board-certified orthopedic surgeon who specializes in all conditions involving the foot and ankle region. She is based in northern Virginia. Learn about our Medical Review Board Eva Umoh Asomugha, M.D. on November 13, 2020 Print A watershed zone of the tendon is a part of the tendon tissue that has the weakest blood supply. Watershed zones are important because they are the areas of the tendon that are prone to injury. Konstantin Inozemtsev / Getty Images There are hundreds of tendons in our bodies, yet we commonly see only a select few tendon problems. These problem types of tendonitis occur in watershed zones of the tendon where the blood supply to that specific area of tissue is furthest away. The blood vessels that feed oxygen and nutrients to the tissue are far up and down the tendon, and must filter to the watershed zone through small capillaries. This watershed zone relies on distant blood supply and is therefore prone to injury. Tendons with watershed zones that are prone to tendonitis or tendon ruptures include: Achilles tendonRotator cuff tendonPosterior tibial tendonTennis elbow A watershed in nature is an area of land where the water flow is directed to a specific river or body of water. The ridges and mountain tops are furthest from these large bodies of water, much like the watershed zones of tendons are furthers from the strongest blood flow. Was this page helpful? Thanks for your feedback! Get exercise tips to make your workouts less work and more fun. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit