Hilar Abnormality in the Left Lung: Left Pulmonary Artery Posterior to the Left Mainstem Bronchus

The thoracic cavity contains vital cardiovascular and pulmonary structures. Few congenital anatomical variations in the bronchial tree and pulmonary vasculature have been reported. Understanding such variants is crucial during surgical procedures that involve the thorax. During routine dissection of an 89-year-old male cadaver as part of a first-year anatomy course, an anomaly of the bronchial tree was discovered. The left lung hilum was notable for the pulmonary artery being posterior to the mainstem bronchus. The case report describes normal lung development and anatomy and the significance of this novel variation in which has not been previously described in the literature.