What is the anatomical location and course of the pulmonary artery?

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Last updated: September 22, 2026 • View editorial policy

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Pulmonary Artery Location

The pulmonary artery originates from the right ventricle of the heart, exits anteriorly, and bifurcates into right and left main branches that course to their respective lungs, with the main trunk positioned anterior to the ascending aorta in the mediastinum 1.

Anatomical Course and Relationships

Origin and Main Trunk

  • The pulmonary artery (PA) trunk emerges from the right ventricle
  • It courses anteriorly and superiorly in the mediastinum
  • The PA trunk should normally be smaller in diameter than the ascending aorta (AA) and descending aorta (DA) 1
  • The main PA is positioned anterior to the ascending aorta

Bifurcation and Main Branches

The main pulmonary artery bifurcates into:

  • Right pulmonary artery: Courses laterally and posteriorly toward the right lung hilum
  • Left pulmonary artery: Extends laterally toward the left lung hilum

Segmental and Subsegmental Branches

The segmental and subsegmental pulmonary arteries parallel the bronchi and are named according to the bronchopulmonary segments they supply 2. This anatomical relationship is critical for surgical planning and interventional procedures.

Key Anatomical Patterns:

  • Proximal branching angles are wide and close to perpendicular 3
  • Distal angles between segmental and subsegmental arteries are narrower (30-45°) 3
  • Segmental artery diameters range from 3.04 to 9.29 mm 3
  • Segmental artery lengths range from 9.09 to 53.91 mm 3

Important Anatomical Relationships

The pulmonary artery branches follow the anatomy of the airways (windpipe and bronchi) 1, which is clinically relevant when interpreting imaging and planning procedures.

Clinical Significance

Anatomical Variations

  • Considerable anatomic variations exist, particularly in the upper lobes 2
  • Variations include differences in number or presence of accessory arteries from adjacent segments 2
  • The right upper lobe shows multiple branching patterns: bifurcation (most common at 36/67 cases), trifurcation (16/67), and single branching (8/67) 4
  • Variations were observed in approximately 12% of surgical cases (10 of 85 lobectomy patients) 5

Distance Measurements for Interventional Procedures

For pulmonary artery pressure monitor implantation 6:

  • Right PA implant site: 4.55 ± 0.64 cm from bifurcation, vessel diameter 17.15 ± 2.87 mm
  • Left PA implant site: 7.4 ± 1.3 cm from bifurcation, vessel diameter 11.83 ± 2.30 mm

Common Pitfalls

  1. Assuming uniform anatomy: The pulmonary arterial tree has significant individual variation that must be assessed preoperatively
  2. Confusing pulmonary arteries with pulmonary veins: Unlike pulmonary arteries that parallel bronchi, subsegmental pulmonary vein branches run within interlobular septa and do not parallel the airways 2
  3. Overlooking the bronchial arteries: The lung receives oxygen and nutrients from bronchial arteries, not pulmonary arteries 1

References

2
Research

Pulmonary vascular anatomy & anatomical variants.

Cardiovascular diagnosis and therapy, 2018

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.