Left lung

Left lung
Mediastinal surface of left lung.
1. Oblique fissure 2. Vertebral part 3. Hilum of lung 4. Cardiac impression 5. Diaphragmatic surface
Latin	pulmo sinister
Gray's	subject #240 1096

The 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.

As seen on the surface, this fissure begins on the mediastinal surface of the lung at the upper and posterior part of the hilum, and runs backward and upward to the posterior border, which it crosses at a point about 6 cm. below the apex.

It then extends downward and forward over the costal surface, and reaches the lower border a little behind its anterior extremity, and its further course can be followed upward and backward across the mediastinal surface as far as the lower part of the hilum.

Lobes

The superior lobe lies above and in front of this fissure, and includes the apex, the anterior border, and a considerable part of the costal surface and the greater part of the mediastinal surface of the lung.

The inferior lobe, the larger of the two, is situated below and behind the fissure, and comprises almost the whole of the base, a large portion of the costal surface, and the greater part of the posterior border. The left lung is actually smaller than the right because of the vital room needed for the heart.

Impressions

On the mediastinal surface, immediately above the hilum, is a well-marked curved furrow produced by the aortic arch, and running upward from this toward the apex is a groove accommodating the left subclavian artery; a slight impression in front of the latter and close to the margin of the lung lodges the left innominate vein.

Behind the hilum and pulmonary ligament is a vertical furrow produced by the descending aorta, and in front of this, near the base of the lung, the lower part of the esophagus causes a shallow impression.

Additional images

Diagram of the respiratory system	Anatomy of lungs	Front view of heart and lungs	Transverse section of thorax, showing relations of pulmonary artery
The position and relation of the esophagus in the cervical region and in the posterior mediastinum, seen from behind	The thymus of a full-time fetus, exposed in situ

See also

• Lingula of left lung
• Right lung

External links

• 00459 at CHORUS
• SUNY Figs 19:06-01 - "Mediastinal surface of the left lung."
• Diagram and quiz at cancer.gov
• Slide at mgccc.cc.ms.us
• Roche Lexicon - illustrated navigator, at Elsevier 02101.002-1
• 879427643 at GPnotebook - "lobes (left lung)"
• Diagram at md.chula.ac.th

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This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated.