Left main bronchus
Updates to Article Attributes
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.
Gross anatomy
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 lobar bronchi 1.
Relations
At left pulmonary hilum:
- superiorly: left pulmonary artery (aortic arch superior to pulmonary artery)
- inferiorly: left pulmonary veins
- anteriorly: left pulmonary veins
- posteriorly: descending thoracic aorta
Blood supply
Left main bronchus is supplied by two arteries, superior and inferior left bronchial arteries directly arising from the descending aorta 2.
Variant anatomy
- tracheal bronchus (pig bronchus)
- cardiac bronchus
- oesophageal bronchus
-<p>The <a href="/articles/trachea">trachea</a> bifurcates into the <strong>right</strong> and <strong>left main bronchi</strong> at the level of the <a href="/articles/carina">carina</a>, supplying air to the <a href="/articles/right-lung">right</a> and <a href="/articles/left-lung">left lungs</a> respectively. Each main or primary bronchus enters the hilum of its lung and gives rise to <a href="/articles/secondary-lobar-bronchi">secondary lobar bronchi</a>, which further divide into <a href="/articles/tertiary-segmental-bronchi">tertiary segmental bronchi</a> supplying the <a href="/articles/bronchopulmonary-segmental-anatomy-1">bronchopulmonary segment</a>.</p><h4>Gross anatomy</h4><p>The left main bronchus is longer, runs more horizontally and is about twice as long as the <a href="/articles/right-main-bronchus-1">right main bronchus</a> <sup>1,2</sup>. It reaches the <a href="/articles/pulmonary-hilum-2">hilum of the left lung</a> at the level of T6, lying inferior to the <a href="/articles/aortic-arch">aortic arch</a> and anterior to the <a href="/articles/oesophagus">oesophagus</a> and <a href="/articles/thoracic-aorta">thoracic aorta</a>.<sup>1,2</sup></p><p>It gives rise to two lobar bronchi, the left upper and lower bronchi <sup>1</sup>.</p><h5>Relations</h5><p>At left pulmonary hilum:</p><ul>- +<p>The <a href="/articles/trachea">trachea</a> bifurcates into the <strong>right</strong> and <strong>left main bronchi</strong> at the level of the <a href="/articles/carina">carina</a>, supplying air to the <a href="/articles/right-lung">right</a> and <a href="/articles/left-lung">left lungs</a> respectively. Each main or primary bronchus enters the hilum of its lung and gives rise to <a href="/articles/secondary-lobar-bronchi">secondary lobar bronchi</a>, which further divide into <a href="/articles/tertiary-segmental-bronchi">tertiary segmental bronchi</a> supplying the <a href="/articles/bronchopulmonary-segmental-anatomy-1">bronchopulmonary segment</a>.</p><h4>Gross anatomy</h4><p>The left main bronchus is longer, runs more horizontally and is about twice as long as the <a href="/articles/right-main-bronchus-1">right main bronchus</a> <sup>1,2</sup>. It reaches the <a href="/articles/pulmonary-hilum-2">hilum of the left lung</a> at the level of T6, lying inferior to the <a href="/articles/aortic-arch">aortic arch</a> and anterior to the <a href="/articles/oesophagus">oesophagus</a> and <a href="/articles/thoracic-aorta">thoracic aorta</a>.<sup>1,2</sup></p><p>It gives rise to two lobar bronchi, the left upper and lower lobar bronchi <sup>1</sup>.</p><h5>Relations</h5><p>At left pulmonary hilum:</p><ul>
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