This document provides information about the anatomy and structures of the right and left atria of the heart. It discusses the key internal features of each atrium, including chambers, valves, veins and arteries, muscle structures, and other anatomical landmarks. It also briefly explains some clinical significance of atrial structures, mentioning how abnormalities like atrial septal defects or atrial fibrillation can impact blood flow and cardiac output. The document aims to educate the reader on the basic internal structures of the atria and their relationships to clinical functions.

1. Name : NUR FARRA NAJWA BINTI ABDUL AZIM
Matric number : 082015100005

2. Understood the basic
anatomical atria
structures internally
Able to relate the
internal structure to
clinical significance

3.  The heart consists of
four chambers, two
atria (upper chambers)
and two ventricles
(lower chambers).
 There is a valve
through which blood
passes before leaving
each chamber of the
heart.

4.  Right Atrium: Structure
- Sinus Venarum (smooth-walled)
- Auricle (rough-walled)
- Pectinati muscles
 Orifices:
- SVC, IVC, Coronary sinus
- Crista Terminalis ("terminal crest")
- Interatrial septum
- Fossa Ovalis
- Annulus ovalis
- Right AV orifice

8.  a collection of smaller veins
that merge together to form
the sinus (or large vessel),
which is located along the
heart's posterior (rear)
surface between the left
ventricle and left atrium
 The coronary sinus collects
the majority of the cardiac
venous blood

9.  smooth muscular ridge in
superior portion of right
atrium that divides musculi
pectinate and the right
atrial appendage from
smooth surface of right
atrium
 may be important in the
genesis of several atrial
arrhythmias, including
atrial reentry and focal
atrial tachycardia

11. Sinuatrial node
• Lies in upper part of sulcus terminalis
• To the right to the opening of superior vena cava.
Atrioventricular node
• In lower part of atrial septum.
• Above the opening of coronary sinus
• Close to the attachment of tricuspid valve

13.  a shallow depression,
forms in the right
atrium just after birth.
 The formation of the
fossa ovalis divides the
heart into two parts, right
and left.
 This allows the
cardiovascular system to
efficiently distribute
oxygenated blood
throughout the body.

14. It is the prominent oval margin of the fossa
ovalis in the right atrium.
Form the upper margin of the fossa ovalis
It is most distinct above and at the sides of
the fossa ovalis and at the below, it is
deficient.

15.  Form by
• Tendon of Todaro (continuation of Eustachian valve of the
inferior vena cava and the Thebesian valve of the coronary
sinus)
• opening of the coronary sinus
• septal cusp of the tricuspid valve
 Angle of Triangel of Koch
• Coronary sinus orifice
• Tendon of Todaro
• Atrioventricular node
 The apex of the triangle of Koch is the location of
the atrioventricular node.

18. Left atrium
• Forms greater part of
base
• Lies behind right atrium.
• Lies anterior to:
• Oblique pericardial sinus
• Oesophagus
• Smooth- walled
 Left Auricle
• Interior is rough due to
muscle ridges

19.  Most of interoir part is
smooth wall
 Musculi pectinati only
at auricle
 Fossa lunata
 Opening
 4 pulmonary veins
 Left antriventricular also
known as mitral
opening with 2 cusps

21. Atrial septal defects
- Blood flows in reverse direction
- Reduce cardiac output

23. ATRIUM
LEFT ATRIUM RIGHT ATRIUM CLINICAL
SIGNIFICANCE
ATRIUM
SEPTAL
DEFECTS
ATRIAL
FIBRILLATION

26. ANY QUESTION ??