What is the cisterna chyli?

• A. Receives the lymphatic drainage in the abdomen, just posterior to the aorta
• B. The main collecting duct for lymph
• C. A lymph node near the base of the neck
• D. An enlarged pouch on the thoracic duct that serves as a storage area for lymph moving toward its point of entry into the venous system

Answer: (D)

The cisterna chyli is an enlarged, dilated pouch at the lower end of the thoracic duct. It serves as a storage reservoir for lymph collected from the lower body, receiving lymph from the lumbar trunks and intestinal trunks. From this sac, lymph moves upward through the thoracic duct toward the left venous angle where it enters the bloodstream. This description—an enlarged pouch on the thoracic duct that stores lymph moving toward its entry into the venous system—best fits what the cisterna chyli is. It is not the main lymphatic duct itself, not a lymph node, and not a structure near the base of the neck.