Heart

HEART

Heart   

Hollow muscular organ Pyramidal in shape Lies within the pericardium in the mediastinum

Surface Markings of the Heart 

Apex: left ventricle 

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5th (L) ICS 3 ½ “ from the midline

Superior border: roots of the great vessels 

2nd (L) CC ½” from edge of sternum to 3rd ® CC ½” from edge of sternum

Surface Markings of the Heart 

Right border: right atrium 

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Left border: left ventricle 

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3rd ® CC ½” from the edge of sternum downward to 6th ® CC ½” from the edge of sternum 2nd (L) CC to the apex

Inferior border: right ventricle and apical part of (L) ventricle 

6th ® CC to apex

Cardiac Borders of the Heart    

Right: right atrium Left: Left auricle and left ventricle Lower: Right ventricle Apex: Left ventricle

Walls of the heart 

Epicardium 

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Myocardium 

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Outer visceral layer of serous pericardium Middle, thick layer of cardiac muscle

Endocardium 

Inner, thin layer of endothelial layer

Structure of the Heart 

Atrial part: atrial septum 

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Runs from anterior wall backward and to the right

Ventricular part: ventricular septum Runs obliquely  Upper part: thin membranous  Lower part: thick muscular 

Skeleton of the Heart 

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Fibrous rings that surrounds the AV, aortic and pulmonary orifices Continous with the membranous part of the ventricular septum Supports the bases of the valve cusps Prevent the valve from stretching and becoming incompetent

Chambers of the Heart    

Right atrium Right ventricle Left atrium Left ventricle

Right Atrium  

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Anterior to the left atrium Consists of a main cavity and an auricle External vertical groove: sulcus terminalis Internal ridge: crista terminalis Posterior to the ridge: smooth sinus venosus Anterior to the ridge: trabeculated

Right Atrium  

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Superior vena cava: no valve Larger inferior vena cava: rudimentary non-functional valve Coronary sinus: between the IVC and AV orifice 

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With rudimentary non-functional valve

Right AV orifice: anterior to the IVC 

With tricuspid valve

Right Atrium 

Fetal remnants 

Fossa ovalis 

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Foramen ovale

Anulus ovalis 

Upper margin

Right Ventricle 

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Forms the greater part of the anterior surface Anterior to the left ventricle Has thicker wall than right atrium

Right Ventricle 

Internal surface: trabeculae carnae 

Papillary muscle Attached to the ventricular wall  Connected to the cusps of tricuspid valve (chordae tendinae) 

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Moderate band 

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Part of the conducting system (AV bundle)

Simple prominent projections

Right Ventricle 

Tricuspid Valve Guards the AV orifice  3 cusps (anterior, septal, inferior) 

Right Ventricle 

Pulmonary valve 

Guards the pulmonary orifice 

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Infundibulum: funnel shaped

3 semilunar cusps (2 anterior, 1 posterior) 

Open: upward into the pulmonary trunk

Left Atrium  

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Posterior to the right atrium Consists of a main cavity and an auricle Has also rigdes on its interior

Left Atrium 

Four pulmonary vein Through the posterior wall  No valve 

Left Ventricle 

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Situated largely behind the right ventricle Small portion forms the left margin of the heart and the apex Walls are 3x larger than the right ventricle Trabeculae carnae  2 papillary muscles 

Left Ventricle 

Mitral Valve Guards the AV orifice  2 cusps (anterior, posterior) 

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Has chordae tendinae and papillary muscle

Left Ventricle 

Aortic Valve Guards the aortic orifice  Has 3 cusps (1 anterior, 2 posterior)  Has aortic sinus 

Anterior: right coronary artery  Left Posterior: left coronary artery 

Heart Sounds 

1st heart sound 

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Closure of AV valves

2nd heart sound 

Closure aortic and pulmonary valve

Surface Anatomy Of Heart Valves 

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Tricuspid valve: ® half of the sternum at the level of 4th ICS Mitral valve: left of the sternum at the level of 4th CC Pulmonary valve: medial end of the 3rd (L) CC Aortic valve: left half of the sternum at the level of 3rd ICS

Heart Sounds 

Tricuspid valve 

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Mitral valve 

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5th ICS MCL

Pulmonary valve 

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Right half of the lower end of the sternal body

Medial end of (L) 2nd ICS

Aortic valve 

Medial end of ® 2nd ICS

3 Surfaces of the Heart 

Sternocostal surface (anterior) 

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right atrium and ventricle

Diaphragmatic surface (inferior) Right and left ventricles  Right atrium 

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Base (posterior) 

left atrium

Apex of the Heart   

Left ventricle Downward, forward and to the left 5th (L) ICS, 3 ½” from midline

Conducting System of the Heart   

(N): 70-90 bpm Atria first then the ventricles System SA node  AV node  AV bundle  Purkinje fibers 

Sinoatrial Node 

Wall of right atrium in the upper part of the sulcus terminalis just to the right of the opening of the SVC

Atrioventricular Node 

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Lower part of the atrial septum just above the attachment of the septal cusp of tricuspid valve Only route into which impulse travels from the atria to the ventricle Right and Left Bundle Branch Purkinje fibers

Arterial Supply of the Heart 

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Ascending Aorta  Aortic valve  Coronary arteries Within the subepicardial connective tissue

Right Coronary Artery 

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Runs between the pulmonary trunk and right auricle Descends almost vertically in the ® AV groove, and at the inferior border of the heart continues posteriorly along the AV groove to anastomose with the (L) coronary artery

Right Coronary Artery 

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Right conus artery: infundibulum of ® ventricle and upper part of the anterior wall of ® ventricle Anterior ventricular branches: anterior surface of the ® ventricle Marginal branch: largest branch. Runs along the lower margin of the costal surface to reach the apex

Right Coronary Artery 

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Posterior ventricular branches: supply the diaphragmatic surface of the ® ventricle Posterior descending artery: posterior part of the ventricular septum. AV node Atrial branches: anterior and lateral surfaces of the ® atrium. SA node

Left Coronary Artery   

Larger than the ® Supplies the major part of the heart Passes between pulmonary trunk and (L) auricle, enters the AV groove and divides into an anterior interventricular branch and a circumflex branch

Left Coronary Artery 

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Anterior descending branch: anastomose with (L) coronary artery at the posterior interventricular groove. ® and (L) ventricle, anterior part of the ventricular septum Circumflex artery: left atrium and ventricle

Action of the Heart  

Systole Diastole