Cardiac Anatomy

Anatomy of the heart

Cor(L)

Kardia(Gk)

Heart in situ

3 layers of heart (remember three layers of arteries)?

1.Heart 2.Fibrous pericardium 3.Parietal layer of serous pericardium 4.Visceral layer of serous pericardium 5.Pericardial space (cavity) 6.Pleural cavity and lung

pericardium • Fibrous pericardium and serous pericardium • Serous part has two layers;parietal and visceral(epicardium) • Between these two layers of serous part is pericardial cavity(***) hemopericardium(?)

F

cardiac tamponade(?).

To understand ‘potential cavity’ visceral

cavity cavity cavity

parietal

Fibrous pericardium • Attached superiorly to the tunics of great vessels. • to the central tendon of diaphragm below. • and by • sternopericardial ligaments to the sternum.

Serous pericardium • Forms two tubes; • 1. Around the arteries(aorta and pulmonary trunk) and • 2.around the veins entering the heart(SVC,IVC, and • pulmonary veins)

Pericardial sinuses • The space between these tubes forms the transverse sinus and • oblique sinus.

Transverse sinus(***) • Lies posterior to ascending aorta and pulmonary trunk(roots of great arteries) • Can be used to ligate these arteries during cardiac surgery

Oblique sinus • Lies posterior to the left atrium. • Provides space for expansion of left atrium • Related intimately to esophagus posteriorly(***)

E

Clinical relevance • Fluid can collect in the pericardial cavity(“effusion”). • Removal of this fluid is called pericadiocentesis. • Fibrous pericardium is pain sensitive (supplied by phrenic nerves)(***) • Pain from here refers to the shoulder(***)

Chambers of the heart Right atrium,right ventricle(right heart) Left atrium and Left ventricle(left heart)

Heart(surfaces and borders) • The heart is shaped like a pyramid lying on its side. • Presents an apex pointing downwards,forwards and to the left. • Its base lies opposite the apex on the back of the heart.

Apex and base of the heart • Apex is formed by lower,lateral part of left ventricle and is • Situated in the left 5th intercostal space 8-9 cm from midsternal plane. • Base is the posterior surface,formed by left atrium(mainly) and partly by right atrium.

Surfaces of heart • Sternocostal (anterior) surface mainly by right ventricle,partly right atrium and left ventricle. • Inferior(diaphragmatic) surface mainly by left ventricle ,partly by right ventricle. • Right and left surfaces by corresponding atria and ventricles.

BASE(posterior surface)

Diaphragmatic surface

borders • Right border by right atrium(mainly) • Inferior margin by right ventricle(mainly) • Left(obtuse border) mostly by left ventricle •Superior vena cava •Inferior vena cava •Right atrium (blue) •Right ventricle (blue) •Left ventricle (red) •Aorta •Pulmonary trunk

Male or female?

Sulci(grooves) • • • • •

Inter atrial Interventricular(anterior and posterior) Atrio ventricular (CORONARY sulcus) All these sulci meet at the back of the heart. This meeting point is called the “crux”of the heart.

Coronary sulcus • the coronary arteries run in this sulcus.

Right atrium • • • •

Receives SVC IVC Coronary sinus(carrying the venous blood from the heart itself) and anterior cardiac veins

Note sulcus terminalis

RA

Interior of right atrium All the chambers of the heart have rough and smooth parts!!!

• Rough part(anterior part) has a vertical ridge “crista terminalis” and musculi pectinati(teeth of a comb) • smooth part (posterior part) is called sinus venarum • The inter atrial septum presents a oval depression“fossa ovalis”

Interior of right atrium

The history of fossa ovalis(***) • In fetal life, the lungs do not function • Hence the left heart depends on right heart for blood supply • Blood from right atrium is shunted through an opening in the interatrial septum(foramen ovale) • This foramen closes after birth to form fossa ovalis and its prominent edge is called “ limbus fossa ovalis”

openings in the right atrium • Openings of SVC,IVC,Coronary sinus • Right atrio ventricular orifice(tricuspid orifice) which is guarded by the tricuspid valve

•The SA node is located at the junction of the superior vena cava with the right atrium.

Other valves in the right atrium • Valve of IVC and valve of coronary sinus(rudimentary)

Triangle of KOCH A triangular area close to the Opening of coronary sinus. Contains A-V node.

Boundaries •base of the septal leaflet of the tricuspid valve inferiorly •anterior margin of the coronary sinus orifice •tendon of Todaro anterosuperiorly

Interior of right ventricle • Rough part presents trabeculae carnae, papillary muscles and chordae tendinae • This part is also called inflow tract • 3 papillary muscles • (anterior,posterior and • septal)

Note the walls and interior of right ventricle

Interior of right ventricle • Smooth part is called “infundibulum”(out flow tract) • This leads to pulmonary trunk. • a special trabeculum connects the interventricular septum and anterior papillary muscle(moderator band or septo marginal band)

Tricuspid valve (right A-V valve) • Cusps are anterior,posterior and septal • Chordae tendinae are attached to these

Pulmonary valve (semi lunar valve) • The out flow tract is guarded by pulmonary valve • Has three semi lunar cusps

Semilunar valve Ascending aorta

(aortic valve)

Interior of Left ventricle • Rough part(inflow tract) • presents trabeculae carnae,papillary muscles and chordae • Two papillary muscles; anterior and posterior • Smooth part is called ‘vestibule’ which leads to the aortic opening

Mitral valve (left A-V valve) • Two cusps; anterior and posterior

Mitral valve and chordae in action

Aortic valve (semi lunar valve) • The outflow tract is guarded by aortic valve • Has three semi lunar cusps

Study this slide

Interventricular septum(***) parts • Muscular part and membranous part • Muscular part is the major part of the septum • Membranous part is usually deficient in VSD

What is Swiss-cheese septum???

Fibrous skeleton of the heart • The valvular openings are kept in position by • Fibrous rings around these places called “skeleton of the heart” • The myocardium originates from this

Cardiac plexus (nerve supply of the heart)

Clinical anatomy • ASD(atrial septal defect) • VSD (ventricular septal defect) • PDA(Patent Ductus Arteriosus)

what is ductus arteriosus?

P A M T

Position of the valves