Maj Dr Poonam Singh Department Of Anatomy Nepal Army Institute of Health Sciences

1. THE HEART
MAJ DR POONAM SINGH
DEPT OF ANATOMY
NAIHS

2. Chambers of the HEART

4. RT ATRIUM

5. 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

6. 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

7. Rt Atrium- Internal features
Smooth
part

8. Internal Features
Rt Atrium Consists of
1. SINUS VENARUM- post smooth part ( Rt horn of
sinus venosus)
1. ATRIUM PROPER- ant rough part
2. CRISTA TERMINALIS - smooth muscular ridge
separating these two parts

9. SINUS VENARUM
 Posterior smooth part
 FEATURES
1. Opening of SVC
2. Opening of IVC
- Eustachian valve -semilunar  NONFUNCTIONING
3. 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

10. ATRIUM PROPER or PECTINATE PART
 Crista Terminalis
 Musculi Pectinati
 Sponge-like network of muscular ridges : auricle

11. 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

12. -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

13. Internal Features

15. 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

16. 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

17. OSTIUM SECUNDUM
ASD

18. Right ventricle

19. RIGHT VENTRICLE
• Thick –walled triangular chamber
• Internal features:-
1. Large lower rough inflowing part
2. Small upper outflowing part Infundibulum
3. Infundibulo-ventricular crest/ supraventricular
crest

20. 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

21. Left atrium

22. 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 valves
2. Venae cordis minimae
3. Left atrioventricular orifice

23. Left ventricle

24. • 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 orifice
2. Aortic orifice

26. Differences between the right & left ventricles
RIGHT 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

27. VALVES OF THE HEART
1. Pair of AV
valves
2. Pair of
semilunar
valves

28. 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.

29. Positions of cusps in the pul & aortic
valves
• Pulmonary:- right ant, left ant, post
• Aortic:- right post, left post, ant

30. CONDUCTING SYSTEM

31. 1. External features, location, shape, sulci &
grooves
2. Chambers of the heart
3. Fibrous skeleton of the heart
4. Conducting system
5. Blood supply

32. Right atrium

33. Left atrium

34. Right ventricle

35. Left ventricle