Venous drainage refers to the process by which deoxygenated blood is collected from various tissues and organs and returned to the heart. This system primarily involves veins, which are blood vessels that carry blood back to the heart after it has delivered oxygen and nutrients to the body's cells. The major veins involved in this process include the superior vena cava and inferior vena cava, which channel blood from the upper and lower parts of the body, respectively. In addition to these large veins, smaller veins, known as venules, collect blood from capillaries and merge to form larger veins. The jugular veins drain blood from the head and neck, while the pulmonary veins carry oxygenated blood from the lungs back to the heart. Proper venous drainage is essential for maintaining healthy circulation and overall bodily function.