Medial Orientation of the Oblique Fissure of the Right Lung

Description

Medial (hilar) anatomy of the right lung is presented in a sagittal orientation, with the oblique fissure (fissura obliqua, major or great fissure) cutting posteroinferiorly from the upper posterior thorax toward the anteroinferior border. Superior to this cleft lies the superior lobe, while the inferior lobe occupies the lower and posterior portion of the lung, the two separated by a fissure that runs deep toward the lung parenchyma rather than remaining a superficial groove. Medially, the concave hilar surface would border the mediastinum, with the fissure approaching but not crossing the hilum where the bronchus and pulmonary vessels enter. Understanding the medial orientation of the oblique fissure matters when you correlate surface anatomy with CT or when you teach lobar localization of disease on a lateral chest radiograph, because a fissure that courses obliquely in the sagittal plane explains why posterior basal pathology often belongs to the lower lobe even when it projects high on a frontal view. It also frames common patterns of spread, such as pleural effusions tracking along the major fissure or lobar collapse (atelectasis) producing volume loss bounded by the fissure, which can mimic a mass if you forget the expected line of separation. A clean fissural boundary is also a surgical roadmap. Use this figure in thoracic anatomy labs, radiology teaching files (lobar anatomy on CT and CXR), and operative planning materials for right lower lobectomy or segmentectomy where fissure-based dissection and incomplete fissures affect air leak risk. Anatomical accuracy verified by SciePro's Medical Advisory Board.