What is the main collecting duct in lymphatic system?

The main collecting duct in the lymphatic system is called the thoracic duct. It is located in the thoracic cavity, on the left side of the body, and is responsible for collecting lymph from all over the body and transporting it to the bloodstream. The thoracic duct begins at the cisterna chyli, which is a small sac located at the junction of the lumbar and thoracic regions. From there, it ascends through the thoracic cavity, passing through the aortic opening in the diaphragm, and empties into the left subclavian vein. The thoracic duct is about 40-45 cm in length and is the largest lymphatic vessel in the body.