Cardiac anatomy

Question 1

Apex beat

Answer 1

Left 5th intercostal space, mid-clavicular line

Question 2

Right heart border

Answer 2

SVC – right atrium

Question 3

Left heart border

Answer 3

Aortic knuckle – left pulmonary artery – LA appendage – left ventricle

Question 4

Anteriorly

Answer 4

Mainly right ventricle

Question 5

Posteriorly

Answer 5

Mainly left atrium and pulmonary veins

Question 6

Mediastinum

Answer 6

Area between right and left pleura, divided as follows:
- thoracic plane between sternal angle and T4/5 divides superior and inferior mediastinum.

Question 7

Pericardium

Answer 7

Divides anterior, middle and posterior mediastinum.
Consists of fibrous (parietal) and visceral layers.

Question 8

Pericardial space

Answer 8

Is a potential space.
Rapid collection of pericardial fluid is restricted and impairs blood filling – cardiac tamponade.
Pleural reflection allows drainage of pericardial fluid from the left of the xiphisternum.

Question 9

AV valves

Answer 9

Are an intrinsic part of their ventricle
Mitral and tricuspid.
Disorders of the ventricle often affect function of the relevant Atrioventricular valve.
Papillary muscles (part of ventricle) attach to atrioventricular valves via chordae tendinae.

Question 10

Semilunar valves

Answer 10

An intrinsic part of their great artery.
Aortic and pulmonary
Disorders of the aorta or pulmonary artery often affect function of their respective valves.

Question 11

Pulmonary artery and vein

Answer 11

Arterial blood is blood leaving the heart – not always fully oxygenated (PA).
Venous blood is blood returning to the heart – not always deoxygenated (PV).
The pulmonary artery carries deoxygenated blood from the heart.
The pulmonary veins carry oxygenated blood back to the heart.

Question 12

Left ventricle

Answer 12

Thick walled and muscular.

Question 13

Right ventricle

Answer 13

Thin muscular wall

Question 14

Atria

Answer 14

Thin walled

Question 15

Left atrium

Answer 15

Four pulmonary veins drain into it.

Question 16

Right atrium

Answer 16

Has smooth (from sinus venosus) and trabeculated (from original atrium) portions
Crista terminalis separates smooth and trabeculated portions of right atrium.
Fossa ovalis is the remains of the foramen ovale which was patent in foetal life.

Question 17

Coronary arteries

Answer 17

Arise from the aortic root sinuses and supply the heart itself.
Coronary arteries are epicardial and therefore accessible to the surgeon (bypass surgery).
Two main coronary arteries, left and right.
Coronaries are functional end arteries, unless collateral supply has developed.

Question 18

Left main stem

Answer 18

Divides into left anterior descending (LAD) and circumflex (Cx) branches.

Question 19

Left anterior descending (LAD)

Answer 19

Runs in the anterior interventricular groove.
The LAD gives off septal and diagonal branches to the septum and left ventricular myocardium.

Question 20

Circumflex (Cx)

Answer 20

Runs in the left atrioventricular groove.
The Cx gives off obtuse marginal branches to the posterolateral LV wall.
In 10% the Cx provides the posterior descending artery (PDA).

Question 21

Right coronary artery

Answer 21

Runs in the right atrioventricular groove. Usually supplies sinus node, AV node and branches to the anterior RV wall.
Distal RCA branches into posterolateral and posterior descending arteries (latter in about 70% of people).
The posterior descending artery runs in the posterior interventricular groove and supplies inferior septum and LV.
Dominance refers to the artery (RCA or Cx) which supplies the posterior descending artery.

Question 22

Dominance

Answer 22

Most people (70%) are right dominant – RCA supplies the PDA (posterior descending artery).
About 20% are co-dominant – RCA and Cx both help supply the PDA.
About 10% are left dominant – Cx supplies the PDA.