Right Atrium of human heart This PPT help to understand the external and internal structures of right atrium. sulcus terminalis on external surface of rt atrium, crista terminalis on internal side of rt. atrium, interior is divided into rough anterior part and smooth posterior part ( sinus venarum) superior and inferior venae cavae drains deoxygenated blood into rt. atrim there is Eustachian valve to guard the opening of IVC and Thebesian valve to guard the opening of coronary sinus septal wall presents fossa ovalis with its border limbus fossa ovalis

1. Rt Atrium
DR KARLE GEETANJALI
PROFESSOR, RACHANA SHARIR,
PMT,S AYURVED COLLEGE,
SHEVGAON

2. Introduction-
Rt atrium is receiving chamber for deoxygenated blood. It
receives deoxygenated blood from the superior and
inferior vena cavae, from the coronary veins & from the
venae cordis minimae.
Rt atrium pumps the blood through the right
atrioventricular orifice(guarded by the tricuspid valve) into
the right ventricle.
.

4. Location and contribution in parts of
heart-
The right atrium is somewhat quadrilateral chamber
situated behind and to the right side of the heart. It is
composed of a main cavity and a small anteriorly
extending part called auricle.
The right atrium forms the right border of the heart.
It contributes in the formation of anterior surface and base
of the heart.

5. External Features-
The right atrium receives superior vena cava (SVC) at its upper end
and the inferior vena cava(IVC) at its lower end.
The upper anterior part is prolonged to the left to create the right
auricular appendage, the right auricle. The margins of the auricle are
notched. The right auricle overlaps the roots of the ascending aorta
and pulmonary trunk

6. Ext features conti..
Sulcus terminalis- A shallow vertical groove that extends along the
right border of heart, in between the superior and inferior vena
cavae.
SA node is located at the upper part of this sulcus. Internally it
corresponds to crista terminalis.
The right atrioventricular groove lodges the right coronary artery
and the small cardiac vein.

7. Internal structure of right atrium-
The interior of the right atrium is divided into 2 parts:
1) smooth posterior part – the sinus venarum,
2) Rough anterior part – the atrium proper.
smooth and rough parts are separated from each other by
crista terminalis.

9. 1) Smooth part-
Presents following structures-
1.Opening of SVC at upper end
2.Opening of IVC at lower end, this opening is guarded by semilunar valve
or Eustachian valve .
3.Opening of coronary sinus- The coronary sinus receives blood from the
coronary veins. It opens into the right atrium between the inferior vena cava
and the right atrioventricular orifice. The opening of coronary sinus is
guarded by coronary valve or Thebesian valve
4.Vanae cordis minimae are small openings of smallest cardiac veins

10. 2)Rough anterior part-
anterior part is rough due to musculi pectinate, the muscle fibres
running forward from crista terminalis.
Musculi pectinate are numerous in auricle.

11. Septal wall of the right atrium-
embryologically this part is developed from septum primum and septum
secundum.
The septal wall inside presents the following features:
1)Fossa ovalis, a shallow oval/saucer-shaped depression in the lower part,
created by septum primum. – It represents the site of foramen ovale in the
foetus.
2) Annulus ovalis/limbus fossa ovalis, creates the distinct upper and lateral
margin of the fossa ovalis. – It represents the free edge of the septum
secundum.
3). Triangle of Koch, a triangular area bounded in front by the base of septal
leaflet of tricuspid valve, behind by anterior margin of the opening of coronary
sinus and above by the tendon of Todaro- a endocardial ridge. – The
atrioventricular node is located in this triangle

12. Thank you!!!
Special thanks to my student Shruti Rasal for diagram of internal
structure of rt atrium,
Durva Pawar for diagram of ant. Veiw of heart