Download Coronary Vessels

CORONARY VESSELS
I.
Arterial Supply to Heart
SLIDE 2, 3, 4
A. Coronary arteries and cardiac veins located on the outer surface of the heart, just deep to
the epicardium, usually embedded in fatty tissue of epicardium
1. Tend to run in the coronary sulcus and interventricular sulci
B. Arteries to the heart are left and right coronary arteries
1. They arise from the ascending aorta immediately after it emerges from the left ventricle
2. First branches of aorta
a. Arise from right and left aortic sinuses of proximal ascending aorta
b. Just superior to the aortic semilunar valve (Slide 4)
i. 3 leaflets/cusps on aortic semilunar valve
1. Right, Left, and Posterior
ii. The LCA arises from the left coronary sinus
iii. The RCA arises from the right coronary sinus
3. Supply the myocardium and epicardium
4. Pass around opposite sides of the pulmonary trunk
SLIDE 5, 7, 8, 9
C. Right coronary artery
1. Passes to right side of pulmonary trunk and courses to the right in the coronary
sulcus on posterior aspect of heart
2. Branches
Remember RPM (Right coronary, posterior interventricular, and right marginal)
a. Sinu-atrial nodal branch
 Arises near origin of right coronary artery
 Ascends to supply sinu-atrial (SA) node
b. Right marginal artery
 Courses along right margin of heart
 Does not reach apex of heart
c. Atrioventricular nodal branch
 Arises on posterior aspect of heart near junction of interatrial and
interventricular septa (crux of heart)
 Supplies atrioventricular (AV) node
d. Posterior interventricular artery
 Courses in posterior interventricular sulcus towards apex of heart
 Branches supply both ventricles and interventricular septal branches that
supply the interventricular septum
SLIDE 6 – know this supply R vs L heart
3. Regions supplied by right coronary artery
a. Right atrium
b. Sinu-atrial node (in approximately 60% of people)
c. Atrioventricular node (in approximately 80% of people)
d. Most of right ventricle
e. Part of left ventricle, inferior surface (diaphragmatic surface)
f. Part of interventricular septum (usually the posterior third)
SLIDE 10, 12, 13
D. Left coronary artery
Remember LAC (left coronary, anterior interventricular, circumflex)
1. Passes between left auricle and left side of pulmonary trunk, courses in coronary sulcus
a. Immediately branches into anterior interventricular artery and circumflex artery
b. May give rise to sinu-atrial nodal branch (40%)
2. Anterior interventricular artery (formerly the left anterior descending artery)
a. Courses in the anterior interventricular sulcus to apex of heart
b. At apex, turns around inferior border to anastomose with posterior interventricular artery
3. Circumflex artery
Coronary Circulation
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a. Smaller branch of left coronary artery
b. Courses to left in coronary sulcus around left border to the posterior surface of
heart
c. Gives off a left marginal branch
 Follows left margin of heart to supply left ventricle
d. Gives rise to the AV nodal branch in 20% of cases
e. Commonly terminates in coronary sulcus on posterior aspect of heart before
reaching crux of heart
SLIDE 11
4. Regions supplied by left coronary artery
a. Left atrium
b. Most of left ventricle
c. Part of right ventricle
d. Most of interventricular septum including the atrioventricular bundles
a. These are part of the intrinsic conduction system
e. Sinu-atrial node (in approximately 40% of people)
SLIDE 14, 15, 16, 17
E. Coronary artery dominance
1. Not defined by amount of heart supplied by each coronary artery
a. Defined by which coronary artery gives rise to the posterior interventricular
artery
2. Right dominance is most typical (85-90%)
a. Right and left coronary arteries share equally in blood supply to heart
i. POSTERIOR INTERVENTRICULAR comes off of this, hence why
more dominant
3. Left dominance is rare (10-15%)
a. Posterior interventricular artery is branch of circumflex artery (rarely happens)
4. Co-dominance (“mixed” dominance) is very rare
a. Branches of both right and left coronary arteries reach crux of heart and send
branches to posterior interventricular groove
SLIDE 18
F. Clinical considerations
1. Decreased blood flow in the coronary circulation due to occlusion by an embolus can
result in ischemia and pain (angina pectoris) to the point of damaging heart tissue
(myocardial infarction)
2. The most common area of occlusion is the anterior interventricular artery followed by
the right coronary artery and the circumflex artery
3. Also, atherosclerosis leads to the coronary arterial stenosis
4. Coronary angioplasty and/or bypass surgery are performed to increase blood supply
to the myocardial tissue
II. Venous Drainage of Heart
SLIDE 19
A. Venous drainage is via the coronary sinus and its tributaries, the anterior and small
cardiac veins, and partly by small veins that empty directly into the heart chambers
a. Ultimately makes its way back to the coronary sinus
SLIDE 20
B. Coronary sinus
1. Located in the posterior part of the coronary sulcus (atrioventricular groove) between
left atrium and ventricle
2. Opens into the right atrium between opening of inferior vena cava and right
atrioventricular orifice
3. Opening guarded by semilunar valve of coronary sinus (endothelium fold)
a. Partial, crescent shaped.
b. Doesn’t completely close it off
SLIDE 21
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4. Tributaries include:
a. Great cardiac vein
b. Small cardiac vein
c. Middle cardiac vein
d. Posterior vein of left ventricle
e. Oblique vein of left atrium
SLIDE 22
Venous Structure
Arterial Structure
Great cardiac vein
Anterior interventricular artery
Middle cardiac vein
Posterior interventricular artery
Small cardiac vein
Right marginal artery
C. Great cardiac vein
1. Begins at cardiac apex, courses superiorly in anterior interventricular sulcus
2. Is main tributary of coronary sinus
a. Enters coronary sinus near its origin
3. Drains the areas of the heart supplied by the left coronary artery
D. Middle cardiac vein
1. Begins at cardiac apex
2. Courses in posterior interventricular groove, accompanies the posterior
interventricular artery
3. Drains into coronary sinus near its atrial end
E. Small cardiac vein
1. Courses in posterior atrioventricular groove between right atrium and ventricle
2. Parallels the right marginal artery
3. Drains into coronary sinus as the sinus enters the right atrium
F. Middle and small cardiac veins drain most of the areas usually supplied by the right
coronary artery
SLIDE 23
G. Smaller anterior cardiac veins drain the right ventricle and drain directly into the right atrium
SLIDE 24
H. Small venae cordis minimae (Thebesian veins)
1. Minute vessels that begin in capillary beds of myocardium
2. Open directly into the chambers of the heart, chiefly the atria
3. Function to help prevent the accumulation of interstitial fluid in the myocardium
Slide 3, 25, and 26  what the views will be like in lab
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