Lecture Notes on Left Coronary Artery Anatomy

Overview

• Focus on vessels off the left coronary artery (LCA)
• Importance of understanding differences between vessels
• Identifying vessels in different views

Anatomy Introduction

• Aortic Root: Includes ascending aorta & root
• Cusp Identification:
  • Left cusp: Left coronary artery (LCA)
  • Right cusp: Right coronary artery (RCA)
  • Non-coronary cusp: No coronary branches (due to proximity to pulmonary artery)

Left Coronary Artery (LCA)

• Branches of the LCA:
  • Left Main (LM): First branch, may be short or absent
  • Bifurcation into:
    • Left Anterior Descending (LAD)
    • Circumflex (CIRC)

LAD (Left Anterior Descending)

• Commonly segmental: Proximal, Middle, Distal
• Branches off the LAD:
  • Diagonals: 1 to 4 branches (fewer but larger)
  • Septal Perforators: Many branches (smaller)
• Segmentation:
  • Proximal LAD: before first diagonal
  • Middle LAD: between first diagonal and apex
  • Distal LAD: wraps around apex of heart

Circumflex (CIRC)

• Feeds lateral wall of the heart
• Shorter than LAD
• May segment into proximal, middle, and distal if large
• Ends in the Atrioventricular (AV) Groove

Branches of Circumflex

• Obtuse Marginals (OM):
  • Can be 1 to 3
  • Named sequentially (OM1, OM2, OM3)

Naming Conventions

• Like Follows Like: Vessels of similar type follow patterns
  • Diagonals look like diagonals
  • Septals look like septals
  • OMs look like OMs
• Example of naming based on flow direction
• Ramus Intermedius: A rare trifurcation in coronary anatomy

PDA (Posterior Descending Artery)

• Can branch off RCA or CIRC
• Includes septal perforators
• Can have posterior lateral branches (discussed in another video)

Key Reminders

• Dominant Left Coronary Artery: PDA comes off circumflex
• Mnemonic: D&D for LAD and Diagonals, O for OM (obtuse marginals)

Conclusion

• Basic understanding of LCA anatomy is crucial
• Upcoming topics: Right Coronary Artery (RCA)