Horizontal Fissure of the Right Lung Observed, Medial View

Description

Medial inspection of the right lung emphasizes the horizontal fissure (fissura horizontalis, minor fissure) as it courses transversely from the anterior border toward the midaxillary region, separating the superior lobe from the middle lobe. Along the costal surface, the fissure lies roughly at the level of the fourth rib anteriorly and continues posteriorly to meet the oblique fissure (fissura obliqua). Superior and posterior to this plane sits the upper lobe, while the middle lobe occupies anteroinferior territory and approaches the cardiomediastinal surface. Recognition of the right horizontal fissure is a practical teaching point because it is the anatomic reason the right lung has a distinct middle lobe, with its own bronchopulmonary segments and a characteristic radiographic appearance. It matters in interpretation of lobar collapse and pneumonia patterns, where consolidation confined to the middle lobe may silhouette the right heart border on frontal chest radiographs, and on CT the fissure helps you localize disease to a lobe rather than a segmental distribution. Misidentifying this fissure also complicates bronchoscopy reports and operative planning for a right upper lobectomy versus a middle lobectomy. Common source of confusion. Use this artwork in gross anatomy and radiologic anatomy modules when correlating pleural reflections, fissure planes, and lobar anatomy, and in clinical education materials that explain right middle lobe syndrome, lobar atelectasis, or fissure-guided CT localization. It also fits thoracic surgery and pulmonary medicine publications that need clean labeling of the minor fissure on the right lung from a medial perspective. Anatomical accuracy verified by SciePro's Medical Advisory Board.