Great lymphatic vessels

The great lymphatic vessels, primarily the thoracic duct and the right lymphatic duct, play crucial roles in the lymphatic system by returning lymph to the venous circulation:

• The thoracic duct is the largest lymphatic vessel, originating from the cisterna chyli in the abdomen and ascending through the thorax to drain into the venous system at the junction of the left subclavian and internal jugular veins. It collects lymph from the lower body, left thorax, left upper limb, and left side of the head and neck.

• The right lymphatic duct, much smaller, drains lymph from the right upper limb, right thorax, and right side of the head and neck into the right subclavian vein.

In the limbs, the superficial lymphatic vessels are closely associated with the subcutaneous veins and are organized into networks that drain into regional lymph nodes. For instance, in the lower extremity, lymphatic collectors are found in the subcutaneous tissue and travel towards the popliteal, femoral, and inguinal lymph nodes.In the upper limb, the lymphatic vessels are similarly organized, with superficial collectors coursing alongside veins and draining into axillary lymph nodes.