Right lung

The right lung is divided into three lobes (as opposed to two lobes on the left), superior, middle, and inferior, by two interlobular fissures:

The right lung has a higher volume, total capacity and weight, than that of the left lung. Although it is 5 cm shorter due to the diaphragm rising higher on the right side to accommodate the liver, it is broader than the left lung due to the cardiac notch of the left lung.

Fissures:

The lower, oblique fissure, separates the inferior from the middle and superior lobes, and is closely aligned with the fissure in the left lung. Its direction is, however, more vertical, and it cuts the lower border about 7.5 cm. behind its anterior extremity.

The upper horizontal fissure, separates the superior from the middle lobe. It begins in the lower fissure near the posterior border of the lung, and, running horizontally forward, cuts the anterior border on a level with the sternal end of the fourth costal cartilage; on the mediastinal surface it may be traced backward to the hilum.

Lobes:

The middle lobe is the smallest lobe of the right lung. It is wedge-shaped, and includes the part of the anterior border, and the anterior part of the base of the lung. The superior and inferior lobes are similar to those of the left lung (which lacks a middle lobe).

Impressions:

There is a deep concavity on the mediastinal surface called the cardiac impression, which accommodates the pericardium; this is not as pronounced as that on the left lung where the heart projects further. On the same surface, immediately above the hilum, is an arched furrow which accommodates the azygos vein; while running superiorly, and then arching laterally some little distance below the apex, is a wide groove for the superior vena cava and right innominate vein; behind this, and proximal to the apex, is a furrow for the innominate artery.

Behind the hilum and the attachment of the pulmonary ligament is a vertical groove for the esophagus; this groove becomes less distinct below, owing to the inclination of the lower part of the esophagus to the left of the middle line.

In front and to the right of the lower part of the esophageal groove is a deep concavity for the extrapericardiac portion of the thoracic part of the inferior vena cava.