Left pulmonary artery

Arteria pulmonalis sinistra

CardiovascularBlood vesselsThoraxLeft side

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What it is
The shorter branch: passes to the left in front of the descending aorta and arches over the left main bronchus into the hilum of the left lung; the ligamentum arteriosum links its origin to the aortic arch.
Function
Carries deoxygenated blood to the left lung.
Size
~3 cm long before dividing, ~2 cm diameter.
Clinical note
In the fetus the ductus arteriosus shunted blood from here into the aorta, bypassing the unexpanded lungs; it closes within days of birth.

Nearby cardiovascular structures Aortic arch, Aortic valve, Ascending aorta, Left atrium, Left subclavian artery, Left superior pulmonary vein, Pulmonary trunk, Pulmonary valve, Right pulmonary artery, Superior vena cava