Lymph drains from most of the body into the venous system via which duct?

• A. Right lymphatic duct
• B. Lymphatic trunk
• C. Cisterna chyli
• D. Thoracic duct

Answer: (D)

Most lymph from the body is returned to the venous blood through the thoracic duct. It collects lymph from the lower body and from the left side of the head, neck, and thorax, and empties into the venous system at the left venous angle where the left subclavian and internal jugular veins meet. The right lymphatic duct handles only lymph from the right side of the head and neck, right upper limb, and right thorax, dumping it into the right venous angle. The cisterna chyli is a dilated sac at the base of the thoracic duct that gathers lymph from abdominal and lumbar trunks and the intestinal trunk, acting as a reservoir feeding the thoracic duct rather than being the main drainage path itself. Lymphatic trunks drain specific regions but do not channel most of the body’s lymph into the venous system. So, the duct that carries the majority of lymph into the venous system is the thoracic duct.