Cardiac anatomy

Question 1

From which angle is the RA best viewed?

Answer 1

From the front

Question 2

Which chamber makes up almost all of the posterior surface of the heart?

Answer 2

The left atrium

Question 3

What are the musculi pectinati?

Answer 3

Raised horizontal ridges of muscle which are found on the walls of part of the interior of the right atrium

Question 4

What is the junction between the rough and smooth part of the atrial wall called? What is the ridge sometimes found on the outside of the heart which corresponds to this called?

Answer 4

Crista terminalis

Sulcus terminalis

Question 5

Which veins drain into the right atrium?

Answer 5

SVC, IVC, coronary sinus

Question 6

Where does the coronary sinus open into the right atrium?

Answer 6

Near the septal cusp of the tricuspid valve

Question 7

What is the shape of the RV?

Answer 7

The RV is cresentic in shape as the thicker muscle bulk of the LV causes the interventricular septum to bulge into the RV

Question 8

What are the muscular ridges lining the wall of the RV called?

Answer 8

Trabeculae carnae

Question 9

What are the cordae tendineae?

Answer 9

Delicate fibrous strands which tether the edges of the cusps of the tricuspid/mitral valves to the ventricular wall

Question 10

What do the cordae tendiniae attach to?

Answer 10

Anterior, posterior and (in the case of the RV) septal papillary muscles

Question 11

What name is given to the smooth part of the LV?

Answer 11

The infundibulum. The LV wall becomes smooth as it approaches the pulmonary trunk

Question 12

Can the left atrium be seen from the front of the heart?

Answer 12

Only the left auricular appedage can be seen from the front. The rest of the LA is hidden and is best seen from behind.

Question 13

What is meant by the fibrous skeleton of the heart?

Answer 13

Each of the four heart valves is surrounded by a fibrous ring. These rings are continuous with each other. They not only form the basis for the attachment of their corresponding valve cusps but also form an electrical barrier between the atrial and ventricular muscle. Electrical impulses can spread through the heart muscle but not through the fibrous skeleton

Question 14

Where is the superficial cardiac plexus located?

Answer 14

Beneath the arch of the aorta

Question 15

Where is the deep cardiac plexus located?

Answer 15

In front of the bifurcation of the trachea

Question 16

Describe the sympathetic innervation of the heart

Answer 16

The sympathetic fibres to the heart arise in the upper four thoracic segments T1-T4. From here they pass to the segmental ganglia in the sympathetic trunk and either synapse at this level or ascend to one of the cervical sympathetic ganglia and synapse there. Post ganglionic sympathetic fibres therefore converge on the cardiac plexuses both directly from the upper four thoracic ganglia of the sympathetic trunk, and from the neck via cardiac branches from the cervical sympathetic ganglia. These nerve fibres pass through the cardiac plexuses and on to the SA node.

Question 17

Where do sympathetic fibres innervating the heart synapse?

Answer 17

Sympathetic trunk or cervical sympathetic ganglia

Question 18

Where do parasympathetic fibres innervating the heart synapse?

Answer 18

Cardiac plexuses or walls of the atria

Question 19

Describe the parasympathetic innervation of the heart

Answer 19

Arises from the vagus nerve (CN X). Cardiac branches arise in the neck and then run down to the plexuses. They also arise from the recurrent laryngeal branch of the Vagus nerve and pass from here directly to the cardiac plexuses. Preganglionic parasympathetic synapse either in the plexuses or they pass through these and synpase in the walls of the atria

Question 20

Which branch of the RCA supplies the RV wall?

Answer 20

The marginal branch

Question 21

What parts of the heart are supplied by the RCA?

Answer 21

All of the right atrium and most of the right ventricle. Usually supplies the AV node

Question 22

What is the largest branch of the RCA? Where does it run?

Answer 22

The posterior descending artery. It runs in the interventricular groove on the diaphragmatic surface of the heart towards the apex of the heart

Question 23

What is the name of the groove between the atria and the ventricles which houses the coronary arteries?

Answer 23

The coronary sulcus

Question 24

What are the terminal branches of the left coronary artery (or left main stem)

Answer 24

The left anterior descending artery and the circumflex artery