Watershed area (medical)

Watershed area is the medical term referring to regions of the body that receive dual blood supply from the most distal branches of two large arteries, such as the splenic flexure of the large intestine.

During times of blockage of one of the arteries that supply of the watershed area, such as in atherosclerosis, these regions are spared from ischemia by virtue of their dual supply. However, during times of systemic hypoperfusion, such as in DIC or Heart failure, these regions are particularly vulnerable to ischemia by virtue of the fact that they are supplied by the most distal branches of their arteries, and thus the least likely to receive sufficient blood.

When watershed stroke occurs in the brain, it produces unique focal neurologic symptoms that aid clinicians in diagnosis and localization.