Left main coronary artery
Citation, DOI, disclosures and article data
Citation:
Knipe H, Bell D, Elfeky M, et al. Left main coronary artery. Reference article, Radiopaedia.org (Accessed on 21 Mar 2025) https://doi.org/10.53347/rID-22844
rID:
22844
Article created:
Disclosures:
At the time the article was created Henry Knipe had no recorded disclosures.
View Henry Knipe's current disclosures
Last revised:
Disclosures:
At the time the article was last revised Daniel J Bell had no recorded disclosures.
View Daniel J Bell's current disclosures
Revisions:
21 times, by
11 contributors -
see full revision history and disclosures
Sections:
Synonyms:
- Left main coronary artery (LMCA)
- LCA (coronary artery)
- LMCA (coronary artery)
- Left coronary artery (LCA)
The left main coronary artery (LMCA) or left coronary artery (LCA) is one of the two main coronary arteries that supply the heart with oxygenated blood.
On this page:
Gross anatomy
Origin
The left main coronary artery is a branch of the ascending aorta, with its normal origin in the left aortic sinus, just superior to the aortic valve 1,2.
Course
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.
Branches
Coronary dominance
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.
Variant anatomy
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.
References
- 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
Incoming Links
Articles:
- Anomalous right coronary artery from the pulmonary artery
- Sinoatrial nodal artery
- Anomalous left coronary artery from the pulmonary artery
- Pulmonary trunk
- Ischaemic cardiomyopathy
- Coronary artery-to-pulmonary artery fistula
- Hypoplastic circumflex artery
- Ascending aorta
- Pericardial agenesis
- LCx and LAD arising separately from the left aortic sinus
- Anomalous aortic origin of coronary artery
- Left anterior descending artery
- Circumflex artery
- Prepulmonic coronary course
- Hypoplastic right coronary artery
- Medical abbreviations and acronyms (L)
- Cardiac plexus
- Aortic root
- Transseptal coronary course
- Ramus intermedius artery
Cases:
- Right coronary artery occlusion successfully treated with percutaneous intervention
- Interarterial course of the left coronary artery
- Prepulmonic left coronary artery
- Left coronary artery anomaly
- Anomalous origin of the left coronary artery
- Anomalous right coronary artery from left coronary sinus
- Aortic dissection with pulmonary artery intramural haematoma
- Single coronary artery - Lipton type L-I
- Hypoplastic right coronary artery
- Interarterial course of the left coronary artery
- Aortic dissection - Stanford type A
- Golden S sign
- Transseptal course of left coronary artery
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