The lungs are seen in the intrathoracic space, which is filled by the mediastinum. It corresponds to the connective tissue space which has the heart, vital blood vessels, the trachea with the bronchi, the esophagus and the thymus gland.
The right lung comprises three lobes – inferior, middle and superior lobe that are distinguished by an oblique and deep horizontal fissure. The left lung has two lobes separated by an oblique fissure. The apexes of the lungs expand above the first rib, while both lungs in the thorax rest with their bases on the diaphragm.
They are medially linked with the mediastinum at the hilum. The hilum is a circumscribed region wherein airways, blood and lymphatic vessels and the nerves leave or enter the lungs.