THE HEART

MAJ DR POONAM SINGHDEPT OF ANATOMY

NAIHS

Chambers of the HEART

RT ATRIUM

Right Atrium of heart

Quadrilateral chamber situated behind & to rt of Rt Ventricle

Forms entire rt border, part of ant surface and 1/3 of base of heart

Extent- orifice of SVC to that of IVC

External Features

1. Sulcus Terminalis

2. Rt Auricle:- margins are notched

3. Rt AV groove – Rt coronary artery, small cardiac vein

Rt auricle

AV groove

Rt Atrium- Internal features

Smooth part

Internal Features

Rt Atrium Consists of

1. SINUS VENARUM- post smooth part ( Rt horn of sinus venosus)

2. ATRIUM PROPER- ant rough part

3. CRISTA TERMINALIS - smooth muscular ridge separating these two parts

SINUS VENARUM

Posterior smooth part FEATURES

1. Opening of SVC2. Opening of IVC - Eustachian valve -semilunar NONFUNCTIONING3. Opening of Coronary Sinus

- In lower part of atrial septum - Thebesian valve-semi-circular valve

4. Foramina Venarum Minimarum - openings of venae cordis minimae/ Thebesian veins & ant cardiac veins

ATRIUM PROPER or PECTINATE PART Crista Terminalis

Musculi Pectinati

Sponge-like network of muscular ridges : auricle

INTERATRIAL SEPTUM

Separates rt & lt atrium

Features:

-Fossa Ovalis -Limbus fossa ovalis or annulus ovalis -Triangle of Koch –lodges AV node Antly-base of septal leaflet of tricuspid valve Postly-opening of coronary sinus (its anteromedial margin) Suply-tendon of Todaro

-Tendon of Todaro sub-endocardial ridge extending postly from Central

Fibrous Body towards valve of IVC-Torus aorticus Elevation in anterosuperior part of septum

Caused by bulging of rt post coronary sinus (non-coronary sinus) of ascending aorta

-AV Orifice :- largest opening

Internal Features

Devt of rt atrium

S Venarum- absorbed rt horn of SV

Atrium proper – rt part of primitive atrium

Crista terminalis – upper part of rt venous valve

IVC & C sinus valves – lower part of rt venous valve

Fossa ovalis floor – septum primum

Limbus fossa ovalis – septum secundum

APPLIED ANATOMY

Thrombus formation –rt auricle

Atrial Septal defect – - patent foramen ovale - ostium secundum defect in area of F ovalis includes both defects of SP & SS - endocardial cushion defect with ostium primum ASDs - sinus venosus ASDs –incomplete SV absorption - common atrium – interatrial septum

Atrial Myxoma

OSTIUM SECUNDUM

ASD

Right ventricle

RIGHT VENTRICLE

• Thick –walled triangular chamber• Internal features:-1. Large lower rough inflowing part2. Small upper outflowing part Infundibulum3. Infundibulo-ventricular crest/ supraventricular

crest

Trabeculae Carneae of Right Ventricular chamber

• Sponge- like appearance• 3 types:- ridges, bridges, pillars• Papillary muscles:- 3in no.. Ant, post & septal• Moderator band/ septomarginal trabeculum

Left atrium

Internal features of left atrium

• Smooth• Lt auricle muscular ridges• Ant wall of left atrial cavity presents Fossa

lunata• Openings:- 1. Four pulmonary veins no valves2. Venae cordis minimae3. Left atrioventricular orifice

Left ventricle

• Thick- walled triangular chamber• Internal features:-1. A large lower rough inflowing part ( primitive

ventricle)2. A small upper smooth outflowing part aortic

vestibule ( bulbus cordis)• Trabeculae carneae• 2 papillary muscles:- Ant & post• Openings:-1. Left AV orifice2. Aortic orifice

Differences between the right & left ventriclesRIGHT VENTRICLE LEFT VENTRICLE

RECEIVES DEOXYGENATED BLOOD FROM RIGHT ATRIUM & PUMPS IT TO THE LUNGS THROUGH PUL TRUNK

RECEIVES OXYGENATED BLOOD FROM LEFT ATRIUM & PUMPS IT TO THE WHOLE BODY THROUGH AORTA

WALL THINNER THAN LEFT (1:3) THICKER (3:1)

3 PAPILLARY MUSCLES ( ANT, POST, SEPTAL) 2 PAPILLARY MUSCLES ( ANT, POST)

MODERATOR BAND PRESENT ABSENT

CAVITY Crescentric in c/s Circular

VALVES OF THE HEART

1. Pair of AV valves

2. Pair of semilunar valves

SEMILUNAR VALVES• 3 in no, attached directly to the wall of aorta & pul trunk• Cusps forms small pockets, mouth towards lumen of great BVs• Fibrous nodule at the midpoint of its free edge• Lunule thickened crescentric edge• Open: during ventricular systole, closed: ventricular diastole.

Positions of cusps in the pul & aortic valves

• Pulmonary:- right ant, left ant, post• Aortic:- right post, left post, ant

CONDUCTING SYSTEM

1. External features, location, shape, sulci & grooves

2. Chambers of the heart3. Fibrous skeleton of the heart4. Conducting system5. Blood supply

Right atrium

Left atrium

Right ventricle

Left ventricle