Left main coronary artery

Dr Henry Knipe et al.

The left main coronary artery (LMCA) or left coronary artery (LCA) is one of the two main arteries that supply the heart with oxygenated blood.

It is a branch of the ascending aorta, with its normal origin in the left aortic sinus, just superior to the aortic valve 1-2.

LMCA runs for 5-10 mm as it passes to the left and posterior to the pulmonary trunk before bifurcating 1-2.

Most hearts are right dominant where the PDA is supplied by the RCA. However up to 20% of hearts may be left dominant, where the PDA is supplied by the LAD or LCx or codominant, where a single or duplicated PDA is supplied by branches of both the RCA and LAD/LCx.

For a more in depth discussion of coronary dominance, see the article coronary arterial dominance.

Anatomical variations of the LMCA include 3:

See main article: congenital coronary artery anomalies.

Anatomy: Thoracic
Share article

Article information

rID: 22844
System: Cardiac, Vascular
Section: Anatomy
Synonyms or Alternate Spellings:
  • Left main coronary artery
  • LCA
  • LMCA

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Figure 1: origin of coronary arteries
    Drag here to reorder.
  • Drag
    Case 1: anomalous origin and course LCA
    Drag here to reorder.
  • Drag
    Case 2: anomalous septal LAD
    Drag here to reorder.
  • Drag
    Case3: left dominant circulation
    Drag here to reorder.
  • Updating… Please wait.

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.