The Thoracic Duct

Key points

• • It commonly begins from a saccular dilatation, the cisterna chyli, which is variable and sometimes absent, in front of the first and second lumbar vertebrae, collecting lymph from the intestines and the lower half of the body.
• • It enters the thorax through the aortic opening of the diaphragm and at first ascends to the right of the midline between the aorta and the azygos vein.
• • At about the level of the fifth thoracic vertebra it crosses to the left side and continues upward to the root of the neck.
• • It drains into the junction of the left internal jugular and left subclavian veins (the left venous angle), returning lymph to the blood.
• • It carries lymph from the whole body except the right upper quadrant, meaning the right side of the head and neck, the right upper limb, and the right side of the thorax.
• • That right upper quadrant is drained separately by the right lymphatic duct, which opens into the right venous angle.