Variations in Pulmonary Fissure: A Source of Collateral Ventilation and Its Clinical Significance

Oblique and horizontal fissures divide the lungs into lobes. Assessing the incompleteness or absence of fissures is important when planning any surgical procedure in this region. This study aimed to investigate the incidence of variations in the fissures and their implication in clinical practice. The sample consists of 70 formalin-fixed lungs (32 right and 38 left lungs). These lungs were assessed for complete, incomplete, and absent fissures and any variations in the fissures on the sternocostal and mediastinal surfaces. Oblique fissure was incomplete on the sternocostal surface in 18.75% and 21% and on the mediastinal surface in 25% and 21% on the right and left lungs, respectively. Additionally, it was absent in 10.5% of the left lung samples. The horizontal fissure was incomplete in 12.5% on both surfaces and was absent in 25% on the right lung samples, of which 50% had no oblique fissure. No accessory fissure was seen in any of the lungs. Incomplete and absent fissures can be observed in the right as well as the left lung, suggesting the source of collateral ventilation. This study imparts important information to pulmonologists doing bronchoscopic lung volume reduction therapy or bronchopulmonary segment resection and also to radiologists and anatomists.