Ring of mammar vein

The ring of mammar vein refer to the passage formed by soft tissue (fascia and muscle) that allows the mammary vein (often the superficial epigastric vein caudalis) to travel to or from the mammary glands. In domestic mammals, this vein drains blood from the udders to the abdominal or thoracic venous system. The ring is particularly visible in lactating females, especially cows and sows, where the mammary vein forms an anastomosis between the superficial abdominal network and the thoracic network.