The hilum is what connects your lungs to their supporting structures and where pulmonary vessels enter and exit your lungs. The hilum of the lung is found on the medial aspect of each lung, and it is the only site of entrance or exit of structures associated with the lungs. Both lungs have a region called the hilum, which serves as the point of attachment between the lung root and the lung. This particular region of the lung can be described as a triangular, depressed area where a lot of anatomical structures enter and leave each lung.

The hilum is as susceptible to disease as any other tissue in your body. Masses caused by conditions like cancer can be particularly concerning. The hilum is the part of your lung that keeps it anchored and acts as a passageway for critical vessels and nerves.

The inner edge of the hilum acts as a channel where a number of structures pass into your lungs. These include your:

• bronchi
• pulmonary veins
• pulmonary arteries
• phrenic nerves
• lymphatic vessels
• nodes
• bronchial arteries

The root of the lung is located at the hilum of each lung, just above the middle of the mediastinal surface and behind the cardiac impression. All of these structures are enclosed by a reflection of the pleura. The lung root also extends inferiorly as a narrow fold known as the pulmonary ligament. The root is formed by the bronchus, the pulmonary artery, the pulmonary veins, the bronchial arteries and veins, the pulmonary plexuses of nerves, lymphatic vessels, bronchial lymph glands, and areolar tissue, all of which are enclosed by a reflection of the pleura.

The root of the lung is the collection of structures that connect the lung to the mediastinum. This includes the pulmonary arteries and veins, the primary bronchi and bronchial arteries, and the pulmonary nerve plexuses and lymphatics. The hilum is the place on the lung where these structures enter and leave the lung.