1. Heart and mediastinum

2. Mediastinum

3. What is the mediastinum?
The region between the lungs, extending from the thoracic inlet to the diaphragm

4. Label… Rib 1 Sternal angle @ T4/5 Superior mediastinum
Anterior mediastinum
Middle mediastinum
Posterior mediastinum
Posterior mediastinum extends inferiorly to the 12th thoracic vertebrae (costodiaphragmatic recess)
Diaphragm

5. Contents of the mediastinum
Superior
Thymus, trachea, oesophagus, aortic arch, SVC, thoracic duct, phrenic & vagus nerves
Anterior
Lymph nodes, thymus (in children), internal thoracic vessels
Middle
Pericardium, heart, ascending aorta, tracheal bifurcation, pulmonary artery, SVC
Posterior
Thoracic part of the descending aorta, azygous vein, splanchnic nerves, sympathetic chain, oesophagus and thoracic duct

6. Heart

7. Label… Arch of the aorta SVC Pulmonary artery Pulmonary trunk RA RV LV
Which structures of the heart sit anteriorly and which sit posteriorly? Right anterior, left posterior
Why? This is because, during development, the heart is a midline structure that rotates to the left
IVC
Apex

8. What are the three layers of pericardium?
Fibrous pericardium – what are its attachments?
Parietal layer of the serous pericardium
Visceral layer of the serous pericardium
What can be used to clamp arterial outflow during cardiac surgery?
Between which layers would a ruptured coronary artery/ventricle/atrium bleed? What could this cause -> in the pericardial cavity (between parietal and visceral layers). Could cause cardiac tamponade.
Fibrous pericardium is attached inferiorly to the central tendon of the diaphragm, hence why it moves inferiorly during inspiration. Also attached anteriorly to the sternum by the sternopericardial ligaments. Its apex is continuous with the adventitia of the great vessels
Transverse pericardial sinus = a passage between two sites of reflected serous pericardium, separating the arteries from the veins

9. What is the function of the fibrous skeleton?
Prevents free conduction of electrical signals from the atria to the ventricles → AVN only route for signal conduction
Also provides structure and support for the heart → it is an attachment point for the AV valves
Mitral valve
Tricuspid valve
Can anyone know what is being shown on this diagram?

10. Atrioventricular valves
Name the AV valves. Where are they located?
Mitral (left ventricle) and tricuspid (right ventricle). Located between the atria and the ventricles
How are they anchored to the ventricle wall?
By tendons (chordae tendineae), which are attached to papillary muscles
What may be the consequences of damage to the papillary muscles?
Valve incompetence and cardiac murmur → mitral/tricuspid regurgitation

11. Semilunar valves Name the semilunar valves. Where are they located?
Aortic (left ventricle) and pulmonary (right ventricle). Located between the ventricles and the aorta/PT
What happens to the valve cusps during systole/diastole?
Posterior RP A LP
During systole the cusps are pushed TOWARD the vessel walls
During diastole blood catches in the pockets and CLOSES the valve
How many cusps are the semilunar valves made of? How are the cusps named? (if this is posterior and this is anterior?) P RA LA
Aortic valve
Anterior
Pulmonary valve

12. Coronary arteries LCA RCA SAN artery SAN R & L atria
65% from RCA,35% from circumflex
Circumflex artery
Left atrium and ventricle
Continues as posterior intraventricular in 40%
Provides AV nodal branch in 20%
LCA
Anterior interventricular artery
R & L ventricles
Majority of septum anterior ⅔
AVN in 20%
RCA
Posterior interventricular artery
Posterior ⅓ of septum
AVN in 80%
RCA is dominant (gives off PIVA) in 60%
LCA is dominant in 40%

13. Label...

14. What is the surface anatomy of the heart borders?
2nd L CC
3rd R CC
5th L ICS midclavicular line
6th R CC

15. Where would you auscultate for the valves?
Mitral
5th left ICS MCL
Tricuspid
4/5th left ICS
Pulmonary
2nd left ICS
Aortic
2nd right ICS

16. Thanks!
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