Final Answer:
Collateral anastomosis includes two or more veins draining the same body region.
Step-by-step explanation:
Collateral anastomosis refers to a vascular arrangement where two or more veins in the same body region are interconnected. This type of anastomosis allows for alternative pathways for blood drainage, providing redundancy in the circulatory system. It plays a crucial role in maintaining blood flow, especially when there is a blockage or restriction in one vein.
Collateral anastomoses are common in various vascular networks, such as those in the circulatory system or the venous drainage of organs. The interconnected veins create an alternative route for blood to bypass potential obstructions, ensuring continuous perfusion and reducing the risk of ischemia.