Name the major structures that pass through the hilum of the lung.

• A. Pulmonary artery; two pulmonary veins; main bronchus; nerves, lymphatics, and bronchial arteries/tracheal branches also pass
• B. Pulmonary artery and main bronchus only
• C. Only the pulmonary veins pass
• D. The thoracic duct passes through

Answer: (A)

The hilum is the doorway where the lung connects to the mediastinum, so the root of the lung brings in the main vessels and airways. The major structures passing through are the pulmonary artery, the main bronchus, and the two pulmonary veins. In addition, the hilum transmits other components that nourish and drain the lung and carry nerves and lymphatics—bronchial arteries, autonomic nerves (via the pulmonary plexus), and lymphatics toward the tracheobronchial nodes. The thoracic duct does not pass through the hilum; it runs in the posterior mediastinum and drains into the left venous angle, not through the lung hilum.