## Hilar Anatomy and Vascular-Bronchial Arrangement **Key Point:** At the lung hilum, the three main structures (pulmonary artery, pulmonary veins, and main bronchus) have a characteristic three-dimensional arrangement that is clinically important for identification and surgical approach. ### Right Hilum — Anteroposterior Arrangement When viewing the right hilum from an anterior perspective (as on a chest X-ray or during anterior thoracotomy): | Structure | Position | Anatomical Level | | --- | --- | --- | | Vein | Most anterior | Inferior/anterior | | Artery | Middle | Between vein and bronchus | | Bronchus | Most posterior | Superior/posterior | **High-Yield:** The standard anatomical teaching for the right hilum (anterior to posterior) is **Vein → Artery → Bronchus (VAB)**. The pulmonary vein lies most anteriorly, the pulmonary artery is in the middle, and the main bronchus is the most posterior structure. **Mnemonic:** **VAB** = Vein, Artery, Bronchus (from anterior to posterior at the right hilum). This is consistent with descriptions in Gray's Anatomy and standard surgical anatomy texts. **Clinical Pearl:** During right hilum dissection or pneumonectomy, the pulmonary vein is encountered first anteriorly, followed by the pulmonary artery, and finally the bronchus posteriorly. This sequence guides safe surgical dissection and prevents vascular injury. Surgeons typically ligate the vein first (anteriorly accessible), then the artery, then divide the bronchus. **Warning:** Do not confuse the right hilum arrangement with the left hilum, where the left pulmonary artery arches over the left main bronchus superiorly, creating a different spatial relationship. On the left side, the arrangement from anterior to posterior is also Vein, Artery, Bronchus, but the superior-inferior relationships differ. *Reference: Gray's Anatomy, 41st edition; Snell's Clinical Anatomy by Regions, 9th edition — Lung Hilum and Root of Lung.* 
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