lung roots (anatomy)
Last reviewed 01/2018
The lung roots are the regions apposing the mediastinal surfaces of the lungs on each side where there is transit to and from the lung of:
- bronchi
- pulmonary arteries
- pulmonary veins
- bronchial vessels
- sympathetic nerves
- parasympathetic nerves
- lymphatics
The region of the lung where the root joins it is termed the hilus; it is approximately central upon the diaphragmatic surface of the lung. The root is ensheathed by the parietal pleural layer where it merges with the visceral pleura at the isthmus; it forms a layer which hang down into a loose fold inferiorly. This fold, the pulmonary ligament, provides room for expansion during increased flow of blood through the root.
The roots on each side have a slightly different arrangement of structures across its surface; this is discussed in the submenu.
The relations of the roots include:
- anteriorly: phrenic nerve
- posteriorly: vagus nerve
- superiorly:
- arching over on the right, the azygous vein
- arching over on the left, the aorta