Week 12 Anatomy - The Heart

Question 1

What is the apex of the heart, and from a surface anatomy perspective, where would you find it?

Answer 1

Apex = inferolateral part of left ventricle, “the pointy bit”

Usually found at 5th ICS, mid clavicular line

Question 2

What is the base of the heart? What blood vessels is it associated with?

Answer 2

The posterior aspect of the heart, largely left atrium. Associated with paired pulmonary veins, pulmonary trunk, and superior and inferior venae cavae

Question 3

What vertebral levels do the base of the heart correlate with?

Answer 3

T6-T9

Question 4

What part of the heart forms the anterior aspect?

Answer 4

Right ventricle

Question 5

What part of heart forms diaphragmatic aspect?

Answer 5

Left ventricle

Question 6

What structures form the right heart border on chest X-ray?

Answer 6

Right atrium, SVC and IVC

Question 7

What structures from left heart border on CXR?

Answer 7

Left ventricle

Question 8

Where does the right coronary artery arise from?

Answer 8

Right aortic sinus

Question 9

Describe the course of the RCA?

Answer 9

Runs from aorta, through coronary sulcus (between RA and RV) and gives off ‘right marginal branch’ before wrapping around posteriorly, continuing as ‘Posterior inter ventricular branch of RCA’

Question 10

What structures does the RCA supply?

Answer 10

60% of people, SA node
80% AV node
Supplied RA and RV, posterior inter ventricular septum

Question 11

What are the branches of the RCA?

Answer 11

SA nodal branch
Right marginal branch
AV nodal branch
Posterior inter ventricular branch

Question 12

Where does LCA arise from?

Answer 12

Left aortic sinus

Question 13

Describe course of LCA?

Answer 13

Runs in coronary sulcus between L auricle and pulmonary trunk, then gives off LAD down the inter ventricular groove, and the later circumflex artery which courses around to the posterior aspect of the heart and anastomoses with the RCA

Question 14

What are branches of the LCA?

Answer 14

Circumflex
Left marginal (off the circumflex)
LAD
Lateral/diagonal branch (from LAD)
Perforating interseptal branches

Question 15

What are sites of anastomoses in the coronary circulation?

Answer 15

Left circumflex + RCA
LAD + Post. Int. Artery

Question 16

What is meant by the term ‘dominant circulation?’

Answer 16

Defined by the vessel of origin which supplies the posterior inter ventricular artery. 80% hearts are right circulation dominant, 20% left dominant or co-dominant.

Question 17

What is the location and role of the coronary sinus?

Answer 17

Main vein of heart that runs L –> R within posterior coronary sulcus. Drains blood from small, middle and great cardiac veins

Question 18

What are the layers of the pericardium?

Answer 18

Fibrous (outer)
Serous (visceral and parietal pericardium)

*Parietal pericardium also known as epicardium

Question 19

What is the function of the fibrous pericardium?

Answer 19

Relatively non distensible fibrous connective tissue which provides structure to heart and prevents rapid overfilling, but also the cause of why tamponade can occur

Question 20

From surface anatomy perspective, where does the brachiocephalic vein form?

Answer 20

Behind the stereo-clavicular joint (bilaterally)
Brachiocephalic artery is formed by the confluence of internal jugular vein and subclavian vein

Question 21

What vessel is formed by the union of the R + L brachiocephalic veins?

Answer 21

Superior vena cava

Question 22

What structures does the SVC return blood from?

Answer 22

Everything above the level of the diaphragm (excepts heart and lungs)

Question 23

At what level does the IVC enter the right atrium?

Answer 23

3rd costal cartilage

Question 24

How does the SVC relate to the trachea and the aorta?

Answer 24

Passes anterior to the trachea, and posterolateral to the ascending aorta

Question 25

In order of anterior to posterior, what are the structures of the superior mediastinum?

Answer 25

Thymus Veins Arteries Airway Oesophagus Lymphatic trunk

Question 26

What are the only branches of the ascending aorta?

Answer 26

Coronary arteries

Question 27

How does the aorta relate to the trachea?

Answer 27

Arch of aorta passes anteriorly to the R) pulmonary artery and in front of the carina

Question 28

What are the branches (in order) from the arch of aorta? (Remember, my right arm is stronger)

Answer 28

Brachiocephalic trunk Left common carotid Left subclavian artery

Question 29

At what location does the brachiocephalic trunk divide into RCC and R subclavian vein? (Hint, also same answer for where LCC and L subclavian

Answer 29

At the level of the stereo-costal joint

Question 30

What vessel does the vagus nerve travel with down into the mediastinum after it exits the cranium?

Answer 30

Common carotid artery (bilaterally - travels within carotid sheath)

Question 31

Where does the path of the R and L vagus nerves no longer mirror each other?

Answer 31

As it enters the base of the neck

Question 32

What is the course of the Right Vagus nerve?

Answer 32

Enters thorax anterior to R) subclavian artery, gives off branch of R) recurrent laryngeal nerve (hooks under and back up from subclavian artery) R vagus continues to run postero-inferiorly to the R side of the trachea, posterior to R) brachiocephalic vein, SVC

Question 33

What plexus does the vagus nerve form when it passes below root of R lung?

Answer 33

Right pulmonary plexus, before reforming into a single nerve again before forming R oesophageal plexus

Question 34

What is the course of the L) vagus nerve?

Answer 34

Passes inferiorly from neck alongside left common carotid, before entering mediastinum between LCC and L subclavian artery Travels down to reach the left side of aortic arch, curving medially as to passes over the top of aorta, giving off L recurrent laryngeal nerve Then as it passes posterior to root of left lung, divides to pulmonary plexus, and then onto oesophageal plexus

Question 35

What spinal roots does the phrenic nerve originate from?

Answer 35

C3-C5 (keeps the diaphragm alive!)

Question 36

How does the phrenic nerve travel into the mediastinum? What is the major point of difference to the course of the vagus nerve?

Answer 36

It enters superior mediastinum between subclavian artery (which lies posterior to phrenic nerve) and brachiocephalic vein. Passes ANTERIORLY to root of the lung

Question 37

What is the sinus venarum?

Answer 37

Smooth, thin walled posterior aspect of right atrium into which the SVC, IVC and coronary arteries open into

Question 38

What is the anterior wall of the right atrium composed of?

Answer 38

Rough, muscular wall composed of pectinate muscles