Watershed Zone of Tendon

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 tendon that are prone to injury.

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 tendon
• Rotator cuff tendon
• Posterior tibial tendon
• Tennis 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.