THE THORACIC DUCTS 231 



to a condition of edema and an interference with the 

 functional activities of the tissues. But in health, 

 before this condition of congestion is permitted, the 

 lymphatic vessels collect the excess volume and 

 carry it into the thoracic ducts, which convey it into 

 the venous system. 1 



The Thoracic Ducts. These are two in number, the 

 right and a common trunk. They drain all the smaller 

 lymphatic vessels of the body and open into the veins. 

 The thoracic duct, or common trunk, drains all the 

 vessels of the body, except the right side of the head 

 and neck, the right upper extremity, the right side of 

 the lung and its pleura, the heart and pericardium, and 

 the convex surface of the liver; the latter are drained 

 by the right thoracic duct. The common trunk begins 

 as the receptacuium chyli, situated opposite the second 

 and third lumbar vertebra behind the peritoneum. 

 The duct is 15 to 18 inches in length. It extends from 

 the second lumbar vertebra to the root of the neck, 

 where it empties into the angle of junction of the 

 subclavian and internal jugular veins. It passes 

 through the aortic opening in the diaphragm between 

 the aorta and the azygos vein. In the thorax it lies 

 between the esophagus and aorta on the thoracic ver- 

 tebra; upon reaching the fourth thoracic vertebra it 

 turns toward the left and passes behind the arch of 

 the aorta and at the seventh cervical vertebra empties 

 into the veins as above. 



The right duct is only about one-half inch in length 

 and opens into the junction of the internal and sub- 

 clavian veins in the right side. 



1 The description of the systemic lymphatic vessels and glands 

 are not included, as they are not considered essential to a nurse's 

 knowledge. 



