Anastomoses

An anastomosis is formed by joining two or more branches of an artery or vein to supply blood to a tissue or organ.

One of the critical roles of anastomoses is to establish collateral circulation, which serves as an alternate blood source if one of the arteries or veins becomes obstructed due to injury or infection.

There are three types of anastomoses — arterial, venous, and arteriovenous.

Arterial anastomoses are formed between arteries. They occur mainly in the brain and heart. The circle of Willis in the brain is an example of an arterial anastomosis, which establishes diverse pathways for blood supply to brain tissues.

However, not all arteries participate in anastomotic connections, and those that lack such interconnections are referred to as end arteries.

Venous anastomoses occur between veins and are found throughout the body.

Arteriovenous anastomoses occur between the artery and vein and are prominently observed in the vascular shunt of capillary beds.

Additionally, anastomoses can be intentionally established through surgical interventions such as bypass surgery.