Watershed area (medical)

Watershed area (medical)

A watershed area in medicine refers to the regions of the body that receive dual blood supply from the most distal branches of two large arteries. These areas are particularly vulnerable to conditions such as ischemia and infarction due to their location at the furthest reach of arterial blood supply.

Anatomy

Watershed areas are found in various parts of the body, including the brain, heart, colon, and kidney. In the brain, the watershed or border zone areas are located between the anterior, middle, and posterior cerebral arteries. In the heart, the watershed areas are found between the territories of the left anterior descending artery, the circumflex artery, and the right coronary artery. In the colon, the watershed areas are located between the territories of the superior mesenteric artery and the inferior mesenteric artery.

Clinical significance

Due to their location at the furthest reach of arterial blood supply, watershed areas are particularly susceptible to hypoperfusion and hypoxia. This makes them the first areas to be affected in conditions such as stroke or myocardial infarction.

In the event of systemic hypoperfusion, such as in shock, the blood flow to these areas may be compromised, leading to ischemia and potential tissue necrosis. This can result in clinical conditions such as watershed infarcts in the brain or colon, leading to neurological deficits or colonic ischemia, respectively.

See also

• Ischemia
• Infarction
• Blood supply
• Stroke
• Myocardial infarction