section_path: Structure/Right lung
section_name: Right lung
paragraph_text: Right lung
  
  The right lung has both more lobes and segments than the left. It is divided into three lobes, an upper, middle, and a lower lobe by two fissures, one oblique and one horizontal. The upper, horizontal fissure, separates the upper from the middle lobe. It begins in the lower oblique 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 back to the hilum. The lower, oblique fissure, separates the lower from the middle and upper lobes and is closely aligned with the oblique fissure in the left lung.
  
  The mediastinal surface of the right lung is indented by a number of nearby structures. The heart sits in an impression called the cardiac impression. Above the hilum of the lung is an arched groove for the azygos vein, and above this is a wide groove for the superior vena cava and right brachiocephalic vein; behind this, and close to the top of the lung is a groove for the brachiocephalic artery. There is a groove for the esophagus behind the hilum and the pulmonary ligament, and near the lower part of the esophageal groove is a deeper groove for the inferior vena cava before it enters the heart.
  
  The weight of the right lung varies between individuals, with a standard reference range in men of 155–720 g (0.342–1.587 lb) and in women of 100–590 g (0.22–1.30 lb).