Left main bronchus

The trachea bifurcates into the right and left main bronchi at the level of the carina, supplying air to the right and left lungs respectively. Each main or primary bronchus enters the hilum of its lung and gives rise to secondary lobar bronchi, which further divide into tertiary segmental bronchi supplying the bronchopulmonary segment.

The left main bronchus is longer, runs more horizontally and is about twice as long as the right main bronchus 1,2. It reaches the hilum of the left lung at the level of T6, lying inferior to the aortic arch and anterior to the oesophagus and thoracic aorta.1,2

It gives rise to two lobar bronchi, the left upper and lower bronchi 1.

Relations

At left pulmonary hilum:

Left main bronchus is supplied by two arteries, superior and inferior left bronchial arteries directly arising from the descending aorta 2.

Thoracic anatomy
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Article information

rID: 45879
System: Chest
Section: Anatomy
Synonyms or Alternate Spellings:
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Cases and figures

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    Figure 1: left sided bronchi
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