pulmonary trunk (anatomy)

Last reviewed 01/2018

The pulmonary trunk is the first and largest vessel within the pulmonary arterial tree. It passes deoxygenated blood from the heart to the lungs. It originates from the right ventricle and passes superiorly and posteriorly for about 4-5 cm. During this course, it is ensheathed by the pericardial sac and initially is anterior to the ascending aorta.

At the level of the inferior margin of the carina, approximately T5, the pulmonary trunk divides into right and left pulmonary arteries. At this point its relations are:

  • anterior:
    • left second intercostal space
    • left lung covered by pericardium
  • posterior:
    • and inferior:
      • ascending aorta
      • left coronary artery
    • and superiorly: left atrium
  • inferior: left atrium
  • þ superior: aortic arch

    • left and right:
      • auricles of atria
      • respective coronary arteries