Left pulmonary artery

The left pulmonary artery (LPA) is one of the branches of the pulmonary trunk, branching at the level of the transthoracic plane of Ludwig. It is shorter than the right pulmonary artery and represents a direct posterior continuation of the pulmonary trunk. It arches posterosuperiorly over the superior margin of the left main bronchus and when posterior to the bronchus enters the superior aspect of the hilum of the left lung where it divides into upper (ascending) and lower trunks. 

  • the upper lobar artery supplies the LUL and lies medial to the left main bronchus. This vessel may arise directly from the pulmonary artery or from the descending pulmonary artery.
  • the descending or interlobar artery supplies the lingula of the LUL and the LLL, lying lateral to the left main bronchus. 

In the fetus, the ductus arteriosus connects the proximal left pulmonary artery to the undersurface of the isthmus of the aorta, allowing blood to bypass the lungs. At birth the ductus closes, and overtime fibroses to form the ligamentum arteriosum, which may calcify.

Related pathology

Anatomy: Thoracic
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Article information

rID: 49331
System: Chest, Vascular
Section: Anatomy
Synonyms or Alternate Spellings:
  • PLA

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Cases and figures

  • Figure 1: pulmonary arteries
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