The base of the lung

Lung

The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

is broad, concave, and rests upon the convex surface of the diaphragm

Thoracic diaphragm

In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...

, which separates the right lung

Right lung

The human right lung is divided into three lobes , superior, middle, and inferior, by two interlobular fissures:-Fissures:...

 from the right lobe

Right lobe of liver

The right lobe is much larger than the left; the proportion between them being as six to one.It occupies the right hypochondrium, and is separated from the left lobe on its ventral surface by the falciform ligament; on its posterior surface by the ligamentum venosum for the cranial half, and by...

 of the liver

Liver

The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

, and the left lung

Left lung

The human left lung is divided into two lobes, an upper and a lower, by the oblique fissure, which extends from the costal to the mediastinal surface of the lung both above and below the hilum....

 from the left lobe of the liver

Left lobe of liver

The left lobe is smaller and more flattened than the right. It is situated in the epigastric and left hypochondriac regions. Its upper surface is slightly convex and is moulded on to the diaphragm; its under surface presents the gastric impression and omental tuberosity.-External links: - "The...

, the stomach

Stomach

The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

, and the spleen

Spleen

The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...

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Since the human diaphragm extends higher on the right than on the left side, the concavity on the base of the right lung is deeper than that on the left.

Laterally and behind, the base is bounded by a thin, sharp margin which projects for some distance into the costodiaphragmatic recess

Costodiaphragmatic recess

In the pleural cavity, the costodiaphragmatic recess is a potential space at the posteriormost tips of the cavity, located at the junction of the costal pleura and diaphragmatic pleura...

 of the pleura, between the lower ribs and the costal attachment of the diaphragm.

The base of the lung descends during inspiration

Inhalation

Inhalation is the movement of air from the external environment, through the air ways, and into the alveoli....

 and ascends during expiration

Exhalation

Exhalation is the movement of air out of the bronchial tubes, through the airways, to the external environment during breathing....

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