Pulmonary trunk

Last revised by Joshua Yap on 11 Aug 2022

The pulmonary trunk, also known as main pulmonary artery (mPA), (TA: truncus pulmonalis) is the solitary arterial output from the right ventricle, transporting deoxygenated blood to the lungs for oxygenation.

Gross anatomy

The pulmonary trunk is approximately 50 mm long and 30 mm wide (most authors use 29 mm in males and 27 mm in females (axial width) as the cut-offs of normal 1,5). It arises as a direct superior continuation of the right ventricular outflow tract, separated by the pulmonary valve. As it ascends it slants posteriorly and to the left of the ascending aorta. Together with the ascending aorta, the pulmonary trunk is invested in a common sheath of serous visceral pericardium, anterior to the transverse pericardial sinus.

At the level of the transthoracic plane, the trunk emerges from the fibrous pericardium and divides into the longer right and shorter left pulmonary arteries in the concavity of the aortic arch, anterior to left main bronchus and to the left of the carina.

The left coronary artery passes between the pulmonary trunk (on the left) and the auricle of the left atrium.

The pulmonary trunk gives off various branches. One of them is the right interlobar artery. The right interlobar artery typically measures 16 mm in males and 15 mm in females on a PA chest radiograph 6.

Related pathology

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Cases and figures

  • Figure 1
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  • Figure 2
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  • Figure 3: mediastinum (Gray's illustration)
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  • Figure 4
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  • Figure 5: development from the aortic arches (Gray's illustration)
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