lung (anatomy)
Last reviewed 01/2018
The lungs are two irregular shaped cones occupying the thoracic cavity within the pleural cavities on either side of the central mediastinum. Invested by the visceral pleura, each lung has both an apex, projecting above the medial part of the clavicle, and a base which sits superior to the diaphragm.
The convex costal surface occupies the largest part of a lung's external surface, it lines the deep surface of the thoracic cage (being deeper behind than in front).
The inferior diaphragmatic surface is concave. The right lung is divided into three lobes by oblique and horizontal fissures; the left lung is divided into two lobes as only the oblique fissure is present.
The medial mediastinal surface is the point of junction with the lung roots at the hilum. The lung roots are the passages for the structures vital for normal respiration and maintenance of the lung parenchyma e.g. pulmonary vessels, bronchial vessels, nerves, lymphatics and the bronchial tree. The bronchial tree is a ramifying network of increasingly small air passages which divide the lung into functional areas for gaseous exchange. Vessels and nerves mirror this divergence from the hila to the periphery of the lungs.
pulmonary circulation (anatomy)