Left main coronary artery
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
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.
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 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.
Related Radiopaedia articles
Anatomy: Thoracic
- thoracic skeleton
- thoracic cage
- thoracic spine
- articulations
- muscles of the thorax
- diaphragm
- intercostal space
- intercostal muscles
- variant anatomy
- spaces of the thorax
- thoracic viscera
- tracheobronchial tree
-
lungs
-
bronchopulmonary segmental anatomy (Boyden Classification) (mnemonic)
- left lung
- right lung
- variant anatomy
- lung parenchyma
- hilum
- pleura
-
bronchopulmonary segmental anatomy (Boyden Classification) (mnemonic)
-
heart
- cardiac chambers
- heart valves
- pectinate muscles
- cardiac fibrous skeleton
-
coronary arteries
- coronary arterial dominance
- myocardial segments
-
left main coronary artery (LMCA)
- ramus intermedius artery (RI)
-
circumflex artery (LCx)
- obtuse marginal branches (OM1, OM2, etc))
- Kugel's artery
-
left anterior descending artery (LAD)
- diagonal branches (D1, D2, etc)
- septal perforators (S1, S2, etc)
-
right coronary artery (RCA)
- conus artery
- sinoatrial nodal artery
- acute marginal branches (AM1, AM2, etc)
- inferior interventricular artery (PDA)
- posterior left ventricular artery (PLV)
- congenital anomalies
- innervation of the heart
- fetal circulation
- atrial septum
- endocardium
- myocardium
-
pericardium
- epicardium
- epicardial fat pad
- pericardial space
- oblique pericardial sinus
- transverse pericardial sinus
-
pericardial recesses
- aortic recesses
- pulmonic recesses
- postcaval recess
- pulmonary venous recesses
- pericardial ligaments
- esophagus
- thymus
- breast
- blood supply of the thorax
- arteries
- veins
- superior vena cava (SVC)
- inferior vena cava (IVC)
-
coronary veins
- cardiac veins which drain into the coronary sinus
- great cardiac vein
- middle cardiac vein
- small cardiac vein
- posterior vein of the left ventricle
- vein of Marshall (oblique vein of the left atrium)
- anterior cardiac veins
- venae cordis minimae (smallest cardiac veins or thebesian veins)
- cardiac veins which drain into the coronary sinus
- pulmonary veins
- thoracoepigastric vein
- lymphatics
- innervation of the thorax
Unable to process the form. Check for errors and try again.