Left main bronchus

Tracheobronchial

tree • Lobar and segmental bronchial anatomy - Ganzer Fall bei Radiopaedia

Skalski M, Lobar and segmental bronchial anatomy. Case study, Radiopaedia.org (Accessed on 20 Nov 2022) https://doi.org/10.53347/rID-23285 • CC by-nc-sa 3.0 (modified)

Tracheobronchial

tree • Bronchial anatomy (annotated CT) - Ganzer Fall bei Radiopaedia

Marsh P, Bronchial anatomy (annotated CT). Case study, Radiopaedia.org (Accessed on 20 Nov 2022) https://doi.org/10.53347/rID-59761 • CC by-nc-sa 3.0 (modified)

Tracheobronchial

tree • Lymphatics of the tracheobronchial tree (Gray's illustration) - Ganzer Fall bei Radiopaedia

Hacking C, Lymphatics of the tracheobronchial tree (Gray's illustration). Case study, Radiopaedia.org (Accessed on 20 Nov 2022) https://doi.org/10.53347/rID-85544 • CC by-nc-sa 3.0 (modified)

Radiopaedia • CC-by-nc-sa 3.0 • de

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 individual bronchopulmonary segments.

Gross anatomy

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

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

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

Arterial supply

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

Variant anatomy