Cardiovascular anatomy

Question 1

Name the layers of the pericardium

Answer 1

Fibrous
Parietal
Visceral

Question 2

Describe the attachments of the fibrous layer of the pericardium to surrounding structures

Answer 2

Superior - great vessels
Anterior - sternum
Inferior - central tendon of the diaphragm

Question 3

What is the function of the pericardium?

Answer 3

Stabilize the heart within the thorax whilst permitting free movement of the heart within the pericardial sac during filling and ejection.

Question 4

What is a normal cardiothoracic ratio, how is it calculated and what can causes normal distortion of this ratio

Answer 4

< 50%

Maximal transverse diameter of the heart divided by maximum internal diameter of the thorax

Distortion: AP views
Increased intrathoracic pressure

Question 5

What three structures drain into the right atrium

Answer 5

Superior vena cava
Inferior vena cava
Coronary sinus

Question 6

Name the cusps of all the heart valves

Answer 6

TRICUSPID
Septal
Anterior
Posterior

They attach to the fibrous AV ring superiorly and inferiorly to the chordae tendinae which connect them to papillary muscles connected to the ventricular wall

MITRAL
Anterior
Posterior

Aortic
Left
Right
Posterior

Pulmonary
Left
Right
Anterior

Question 7

Why does the RV appear crescentic in shape

Answer 7

The LV bulges into the RV

Question 8

What is the moderator band in the RV

Answer 8

This is a trabeculae (one of many in the trabeculated muscle wall of the RV) that crosses the RV cavity and carries part of the RV conducting system.

Question 9

What is the smooth walled RV outflow tract called

Answer 9

Infundibulum

Question 10

In what % of adults can a “probe patent” foramen ovale be found?

Answer 10

15%

Question 11

Where do the pulmonary veins drain into the left atrium

Answer 11

Posterior wall of LA

Question 12

How many leaflets does the mitral valve contain and name these

Answer 12

2

Anterior leaflet
Posterior leaflet

Question 13

In what % of people is the SA node supplied by the RCA

Answer 13

65%

Question 14

How many internodal tracts exist between the SA node and the AV node, name these

Answer 14

Anterior internodal tract
Middle internodal tract
Posterior internodal tract

Question 15

What is the function of the AV node

Answer 15

Delay conduction from atria to ventricles
The A-V node is the only electrical link

Abnormal pathways may be responsible for re-entrant tachycardias

Question 16

In what percentage of people is the AV node supplied by the RCA

Answer 16

80%

Question 17

Describe the origin course and main branches of the right coronary artery

Answer 17

Origin: Right aortic sinus –> descends in the AV groove –> gives off right marginal artery –> continues to wrap around to the posterior aspect of the heart and gives rise to the posterior interventricular artery as it descends into the posterior interventricular groove

Question 18

Describe the origin course and main branches of the left coronary artery

Answer 18

Origin: left aortic sinus
divides into the left anterior descending artery (or L. inter-ventricular a.) and left circumflex arteries - the latter giving rise to the left marginal arteries.

LAD gives off septal and diagonal branches

Question 19

Which parts of the heart re supplied by the left anterior descending artery?

Answer 19

Anterior parts of the left and right ventricles

Anterior 2/3rds of the interventricular septum

Question 20

What is right dominance with regard to the coronary circulation

Answer 20

When the posterior descending artery arises from the right coronary artery - true in 85% of people

Question 21

In what percentage of people does the left circumflex artery give rise to the posterior descending artery?

Answer 21

15% = left dominance

Question 22

What % of coronary blood drains into the coronary sinus and where is the coronary sinus

Answer 22

75% of blood - located in the left AV groove on the posterior aspect of the hear adjacent to the left circumflex.

The Great, Middle and small cardiac veins drain into the carotid sinus

Question 23

Which veins drain the anterior aspect of the RV

Answer 23

anterior cardiac veins which drain directly into the RA.

Question 24

What are thebesian veins

Answer 24

Small veins that drain directly into the cardiac chambers

Question 25

How does the PSNS innervate the heart and what are the basic effects

Answer 25

The vagus and recurrent laryngeal nerve send branches via the deep and superficial cardiac plexuses. Post ganglionic fibres pass to the SA node and the AV node with minimal distribution to the ventricles..Reduces rate and force of contraction and causes coronary vasoconstriction. Afferent fibres concerned with cardiac reflexes carried by vagus nerves

Question 26

Where does SNS supply to the heart arise and what are the effects on the rate and force of contraction?

Answer 26

From the lateral horns of the spinal cord T1 - T4. The pre-ganglionic fibres travel to the three cervical ganglia and the upper thoracic sympathetic ganglia. Increase heart rate and force of contraction

Question 27

Which ANS nerves do pain fibres travel with

Answer 27

SNS fibres. The pain fibres travel from the pain receptor to the spinal cord. Might explain why cardiac pain may be referred to the arm or neck.

Question 28

What is the contents of the carotid sheath

Answer 28

Common and internal carotid artery Internal jugular vain Vagus nerve The vein is usually lateral to the artery

Question 29

How is the left subclavian vein different to the right subclavian vein

Answer 29

The thoracic duct drains into the left subclavian vein

Question 30

What is the origin and course of the left subclavian vein

Answer 30

Continuation of the left axillary vein passes over the first and second ribs and under the left clavicle until meeting the left external and then internal jugular veins which form the left brachiocephalic vein which subsequently flows into the superior vena cava.

Question 31

Name the boundaries of the femoral triangle

Answer 31

``` Inguinal ligament (superior) Sartorius muscle (lateral) Adductor longus muscle ```

Question 32

How is the femoral vein located for cannulation

Answer 32

In the midline of the femoral triangle and at the midpoint between the symphasis pubis and the ASIS is the femoral artery. The mnemonic NAVVAN describes the relationship of the nerves, arteries and veins from wither side - the veins are most medial. Find the medial aspect of the femoral a. pulsation

Question 33

What are PICC lines

Answer 33

Peripherally inserted central catheters --> inserted via the basilic vein or the median cubital vein. A valve in the cephalic vein as it drains into the axillary vein makes this less reliable for PICC insertion

Question 34

What % of the population have a superficial ulnar artery and what is the clinical relevance of this?

Answer 34

2% of the population. The superficial ulnar artery lies superficial to the bicipital aponeurosis and immediately adjacent to the median cubital vein --> HIGH RIISK FOR INADVERTANT INTRA-ARTERIAL INJECTION

Question 35

What test must be done before arterial cannulation? Which arteries can be used for arterial cannulation?

Answer 35

Allen's test to ensure collateral flow Radial and ulnar arteries Dorsalis pedis artery also commonly used for a-line insertion Large calibre end arteries may also be used (femoral/axillary) Brachial artery must be avoided!