Lung hilum

The lung hila or roots are found on the medial aspect of each lung. The left and right lung roots are similar but not identical.

Gross anatomy

Left hilum

In the left hilum the left pulmonary artery occupies the upper part. Below this is the left main bronchus. There are two pulmonary veins, one lies in front, and the other lies below the left main bronchus.

Right hilum

In the right hilum the bronchus of the upper lobe and the branch of the right pulmonary artery to the upper lobe originate prior to entering the hilum. Thus, the upper lobe bronchus and artery are found above the level of the right main bronchus and right pulmonary artery. The arteries lie in front of their respective bronchi. The two pulmonary veins are similar to that of the left side, one in front and one below the right main bronchus.

The structures of the lung hilum are enclosed in a sleeve of pleura continuous below with the pulmonary ligament.

In addition to the structures described above, each root contains bronchial vessels, autonomic nerves, lymph nodes and lymphatic channels.