Left main coronary artery
Citation, DOI & article data
The left main coronary artery 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 posterior descending artery (PDA) is supplied by the right coronary artery (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 left main coronary artery (LMCA) include 3:
- in ~15% of patients the LMCA trifurcates
- left anterior descending artery
- left circumflex artery
- ramus intermedius artery
- multiple ostia: separate origin of LAD and LCx (i.e. no LCA)
- single coronary artery (very rare)
- anomalous origin of LMCA from pulmonary artery known as ALCAPA (anomalous origin of the LCA from the pulmonary artery)
- very rare (1 in 300,000 births); high morbidity and mortality in first 12 months of life
- origin of LMCA from right coronary sinus (see Case 1) or non-coronary sinus
See main article: congenital coronary artery anomalies.
- 1. O'Brien JP, Srichai MB, Hecht EM et-al. Anatomy of the heart at multidetector CT: what the radiologist needs to know. Radiographics. 2007;27 (6): 1569-82. Radiographics (full text) - doi:10.1148/rg.276065747 - Pubmed citation
- 2. Kini S, Bis KG, Weaver L. Normal and variant coronary arterial and venous anatomy on high-resolution CT angiography. AJR Am J Roentgenol. 2007;188 (6): 1665-74. doi:10.2214/AJR.06.1295 - Pubmed citation
- 3. Kim SY, Seo JB, Do KH et-al. Coronary artery anomalies: classification and ECG-gated multi-detector row CT findings with angiographic correlation. Radiographics. 2006;26 (2): 317-33. Radiographics (full text) - doi:10.1148/rg.262055068 - Pubmed citation