Cardiac Anatomy

Layers of the pericardium

Visceral pericardium on heart parietal pericardium outside small lubricating fluid.

Sources of deoxygenated blood to RA

SVC, IVC, coronary sinus.

Gross orientation: PA bifurcation

Main PA splits into R and L PA, the right PA travels below aortic arch.

Gross orientation: LA

LA is posterior, directly in front of esophagus.

CXR rib spaces: 1st-2nd space stab on right side wound hits

Aorta

CXR rib spaces: 5th/6th space on medial left stab wound hits

Right ventricle

CXR rib spaces: 3rd+4th space on right side stab wound hits

Right atrium including AV node.

CXR rib spaces: 5th-6th spaces on left side stab wound hits

Left ventricle

Knowledge check: Most exposed chamber to penetrating trauma?

Right ventricle.

Coronal vs Sagital vs Axial View

Coronal: Look the crown in the eyes (from the front)

Sagital: S for from the side

Axial: from the bottom (axx)

Pulmonic vs aortic valve orientation

Pulmonic valve is anterior and left of aortic valve.

RV relationship to sternum

RV sits directly behind sternum.

LA relationship to esophagus

LA sits directly in front of esophagus, enlargement → dysphagia.

Epicardial fat definition

Fat within visceral pericardium directly attached to cardiac chambers; coronary arteries run within it.

Valve types: Semilunar

Aortic (LV→aorta) and pulmonic (RV→PA)

Valve types: AV

Mitral (LA→LV) and tricuspid (RA→RV)

Papillary muscle function + on which valves

Prevent AV valve prolapse during systole. Mitral and Tricuspid

AV groove arteries

RCA in right AV groove, LCX in left AV groove.

Interventricular septum arteries

Anterior: LAD, Posterior: PDA.

RCA course

Travels in AV groove from right coronary cusp → RV → posterior IV septum.

LCA branches

LAD + LCX.

LAD course

Down anterior IV septum → apex → distal inferior wall.

PDA course

Down posterior IV septum, determines dominance

Coronary territories: RCA

Inferior, posterior, diaphragmatic

Coronary territories: LAD

Apex, anterior wall, anteroseptal.

Coronary territories: LCX

Lateral wall, sometimes posterior

Papillary muscle blood supply (posteromedial +anterolateral)

Posteromedial papillary muscle: single supply (RCA or LCX)

Anterolateral: dual supply (LAD + LCX)

Coronary veins

Great cardiac, middle cardiac, small cardiac → converge into coronary sinus.

Coronary sinus drainage

Drains into RA

SA node location + function

High in RA near SVC. Starts beat

AV node location + function

Between valves, near crux. Electrical gatekeeper to ventricles

Bundle branches function

Fast fibers that carry the signal through both ventricles quickly

Blood supply to conduction system

RCA supplies SA node + AV node (85%), LCX supplies AV node (15%), LAD supplies AV bundle