Hilar

Hilar is a term used in medical parlance to refer to the area of an organ where the structures such as arteries, veins, and nerves enter. This term is most commonly used in relation to the lungs, where it refers to the part of the lung where the main bronchus, arteries, veins, and nerves enter and exit. This area is also known as the hilum.

Anatomy

The hilar region of the lung is located in the middle mediastinum, and it is where the structures that form the root of the lung converge. These structures include the main bronchus, the pulmonary arteries and veins, the bronchial vessels, the lymphatic vessels, and the nerves. The arrangement of these structures at the hilum varies between the right and left lungs.

Clinical Significance

Changes in the appearance of the hilar region on imaging studies can indicate a variety of lung diseases. For example, enlarged hilar lymph nodes can be a sign of lung cancer, tuberculosis, or sarcoidosis. Hilar masses may represent lung cancer or other types of tumors. Changes in the position of the hilum can indicate lung collapse or overinflation.

See Also

• Lung
• Bronchus
• Pulmonary artery
• Pulmonary vein
• Lymphatic system
• Nervous system