Right and left coronary artery er course
Coronary Arteries - Origin and Course
Right Coronary Artery (RCA)
- Passes anteriorly, then descends vertically in the coronary sulcus between the right atrium and right ventricle.
- On reaching the inferior (acute) margin of the heart, it turns posteriorly and continues in the sulcus onto the diaphragmatic surface and base of the heart.
| Branch | Course & Supply |
|---|---|
| Atrial branch | Passes in the groove between the right auricle and ascending aorta |
| Sinuatrial (SA) nodal branch | Arises early; passes posteriorly around the superior vena cava to supply the SA node |
| Right marginal branch | Given off at the inferior (acute) margin; continues toward the apex |
| AV nodal branch | Small branch to the atrioventricular node as the RCA reaches the base/diaphragmatic surface |
| Posterior interventricular branch (posterior descending artery, PDA) | Final major branch; lies in the posterior interventricular sulcus |
- Right atrium and right ventricle
- SA node and AV node (in most people)
- Interatrial septum and a portion of the left atrium
- Posteroinferior one-third of the interventricular septum
- Portion of the posterior left ventricle
Left Coronary Artery (LCA)
- Passes between the pulmonary trunk and the left auricle before entering the coronary sulcus.
- Emerges from behind the pulmonary trunk and almost immediately divides into its two terminal branches.
1. Anterior Interventricular Branch (LAD - Left Anterior Descending)
- Continues around the left side of the pulmonary trunk.
- Descends obliquely toward the apex in the anterior interventricular sulcus.
- Often gives off one or two diagonal branches across the anterior surface of the left ventricle.
- Also gives off septal perforators to the anterior two-thirds of the interventricular septum.
- Usually wraps around the apex to end in the posterior interventricular sulcus.
2. Circumflex Branch (LCx)
- Courses to the left within the coronary sulcus, onto the base/diaphragmatic surface.
- Usually ends before reaching the posterior interventricular sulcus (in right-dominant hearts).
- Gives off the left marginal artery (obtuse marginal), which crosses the rounded obtuse margin of the heart.
- Most of the left atrium and left ventricle
- Most of the interventricular septum, including the AV bundle and its branches (bundle of His and bundle branches)
Dominance
| Dominance | Description | Frequency |
|---|---|---|
| Right dominant | PDA arises from RCA; RCA supplies a large portion of the posterior left ventricle; circumflex is relatively small | ~85% (most common) |
| Left dominant | PDA arises from an enlarged circumflex branch; circumflex supplies most of the posterior left ventricle | ~8% |
| Co-dominant | Both RCA and LCx contribute to the PDA territory | ~7% |
Clinical Terminology Summary
| Anatomical Name | Clinical Name |
|---|---|
| Left coronary artery (proximal) | Left main stem (LMS) |
| Anterior interventricular branch | Left anterior descending (LAD) |
| Circumflex branch | LCx |
| Posterior interventricular branch | Posterior descending artery (PDA) |
| Right marginal branch | Acute marginal branch |
| Left marginal branch | Obtuse marginal branch |
Flow chart daw
Medical anatomy flowchart showing the origin and course of the right and left coronary arteries. Clean white background, professional medical diagram style. Title: "Coronary Arteries - Origin & Course" Start with a box at the top: "ASCENDING AORTA (Aortic Sinuses)" Two branches split from it: LEFT SIDE - "LEFT CORONARY ARTERY (LCA) - Left Aortic Sinus" → "Passes between Pulmonary Trunk & Left Auricle" → "Enters Coronary Sulcus" → then splits into TWO branches: Branch 1: "ANTERIOR INTERVENTRICULAR BRANCH (LAD)" → "Descends in Anterior Interventricular Sulcus" → "Diagonal Branches (to anterior LV)" → "Septal Perforators (anterior 2/3 of IVS)" → "Wraps around Apex" Branch 2: "CIRCUMFLEX BRANCH (LCx)" → "Courses LEFT in Coronary Sulcus" → "Obtuse Marginal Branch (left marginal artery)" → "Ends before posterior IVS (right dominant)" RIGHT SIDE - "RIGHT CORONARY ARTERY (RCA) - Right Aortic Sinus" → "Passes Anteriorly → Descends in Coronary Sulcus (between RA & RV)" → "Reaches Inferior (Acute) Margin" → "Turns Posteriorly onto Diaphragmatic Surface" → then splits into BRANCHES: "SA Nodal Branch → Posterior to SVC → SA Node" "Right Marginal Branch → Along Acute Margin → Apex" "AV Nodal Branch → AV Node" "Posterior Interventricular Branch (PDA) → Posterior IVS" At the bottom, a "DOMINANCE" box: "Right Dominant (85%): PDA from RCA | Left Dominant (8%): PDA from LCx | Co-dominant (7%): Both" Use blue color for left coronary system boxes, red for right coronary system boxes, green for the dominance box. Arrows connecting all boxes. Neat, readable font, well-spaced layout.
