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Where are the lungs located within the thoracic cavity?

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Illustration showing different animals and their respiratory organs: a spider with book lungs, a chicken with lungs, a sponge with labeled inflow and outflow pores, a fish with gills, and a caterpillar with spiracles. — Respiratory system Different methods of respiration in animals.

The lungs occupy the majority of the intrathoracic space within the thoracic cavity, situated on either side of the mediastinum—a central connective tissue space that houses the heart, major blood vessels, and other structures.12

Their specific positioning within the thorax is defined by the following anatomical relationships:

Base and Apex: The lungs rest with their bases on the diaphragm, while their apexes extend superiorly above the first rib.1
Medial Attachment: They are connected to the mediastinum at the hilum, which serves as the entry and exit point for airways, nerves, and blood and lymphatic vessels.1
Pleural Lining: The lungs are enclosed by the visceral pleura, while the inner walls of the thoracic cavity are lined by the parietal pleura. A thin film of fluid between these layers allows the lungs to move smoothly against the thoracic wall during breathing.12

Due to the asymmetrical position of the heart, the left lung is smaller in volume than the right lung.1