The rounded, tapered superior end or apex of the lung extends through the superior thoracic aperture into the root of the neck. Here, it lies in close contact to the dome or the cupula of the pleura. The apex of the lung is crossed by the subclavian artery, which produces a groove in the mediastinal surface. The artery, however, is separated from the cupula by the suprapleural membrane. The Left Lung is divided into superior (upper) and inferior (lower) lobes by a long deep oblique fissure. This extends from its costal to its medial surface. The superior lobe has a large cardiac notch on its anterior border, where the lung is deficient owing to the bulge of the heart. The anteroinferior part of the superior lobe has a small tongue-like projection called the lingula. The inferior lobe of the left lung is larger than the superior lobe and lies inferoposterior to the oblique fissure. The Right Lung is divided into superior (upper), middle, and inferior (lower) lobes by horizontal and oblique fissures. The horizontal fissure separates the superior from middle lobes. The oblique fissure separates the inferior lobe from the superior and middle lobes. The superior lobe of the left lung is smaller than that, and the middle lobe is wedge-shaped. Left Lung: 1) Superior (upper) lobe: Apical, Posterior, Anterior, Superior lingular, Inferior lingular. 2)Inferior (lower) lobe: Superior (apical), Medial basal, Anterior basal, Lateral basal, Posterior basal, Right Lung: 1) Superior (upper) lobe: Apical, Posterior, Anterior. 2)Middle lobe: Lateral, Medial. 3) Inferior (lower) lobe: Superior (apical), Medial basal, Anterior basal, Lateral basal, Posterior basal.