Vessels and nerves of the superior mediastinum

Question 1

Where does the superior mediastinum extend to?

Answer 1

extends upwards, terminating at the superior thoracic apeture.

Question 2

Where does the inferior mediastinum extend to?

Answer 2

extends downwards terminating at the diaphragm. It is further divided into the anterior, middle and posterior mediastinum

Question 3

Where do the great systemic blood vessels lie?

Answer 3

within the superior mediastinum, their main branches arise before passing through the superior thoracic apeture

Question 4

What three branches come off the arch of the aorta?

Answer 4

brachiocephalic artery, left common carotid artery, left subclavian artery

Question 5

What does the Brachiocephalic artery go on to supply?

Answer 5

right side of the head and neck and the upper right limb

Question 6

What does the left common carotid go on to supply?

Answer 6

left side of the head and neck

Question 7

what does the left subclavian go on to supply?

Answer 7

left upper limb

Question 8

What are the main branches of the superior vena cava?

Answer 8

the left and right brachiocephalic veins

Question 9

What are the branches of the brachiocephalic artery?

Answer 9

right common carotid and right subclavian artery

Question 10

Where is do superior and inferior mediastinum divide?

Answer 10

sternal angle to the T4 vertebrae

Question 11

what are the borders of the superior mediastinum?

Answer 11

Superior; Thoracic inlet
Inferior: continuous with the inferior mediastinum at the level of the sternal angle
Anterior: manubrium of the sternum
Posterior: vertebral bodies of T1-4
Lateral: pleurae of the lungs

Question 12

What are the other branches of the superior vena cava?

Answer 12

left superior intercostal vein, supreme intercostal vein and Azygous vein

Question 13

What are the main nerves of the superior mediastinum?

Answer 13

Vagus, Phrenic, cardiac nerves and the sympathetic trunk

Question 14

Where does the right vagus nerve run?

Answer 14

runs parallel to the trachea and passes posteriorly to the superior vena cava and the right primary bronchus

Question 15

Where does the left vagus nerve run?

Answer 15

enters the superior mediastinum between the left common carotid and the left subclavian arteries. It descends anteriorly to the aortic arch, before travelling posterior to the left bronchus

Question 16

What arises from the left vagus nerve as it passes under the aortic arch?

Answer 16

Left recurrent laryngeal nerve, it then continues its journey to the larynx in the tracheal-oesophageal groove

Question 17

What is the Ligamentum arteriosum?

Answer 17

it is a remnant of the ductus arteriosum which shunts blood from pulmonary trunk to aorta in the foetus. It is found under the arch of the aorta

Question 18

What are the nerve roots of the phrenic nerves?

Answer 18

C3, C4 and C5

Question 19

which nerve if compressed causes hoarseness of the voice?

Answer 19

left recurrent laryngeal nerve, this can occur due to carcinoma of the oesophagus, mediastinal lymph node enlargement, aortic arch aneurysm or left lung tumour. This is because the left recurrent laryngeal nerve innervates the left vocal cords

Question 20

What is the pericardium?

Answer 20

it is a tough sac which encloses the heart, it is mainly made up of fibrous tissue

Question 21

what does the parietal pericardium cover?

Answer 21

lines the entire pericardial cavity, inner surface with a smooth lining.

Question 22

what does the visceral pericardium cover?

Answer 22

the blood vessels and heart

Question 23

What is the Thymus gland?

Answer 23

it is a primary lymphoid organ which primary function is to promote the development of t cells for the immune system. It is the most anterior structure of the superior mediastinum and sits against the posterior surface of the sternum.

Question 24

what are the other structures of the superior mediastinum?

Answer 24

thymus, trachea, thoracic duct and the sternohyoid and sternothyroid muscles

Question 25

What are the five surfaces of the heart?

Answer 25

anterior (sternocostal), posterior (base), Inferior (diaphragmatic), right pulmonary and left pulmonary

Question 26

What are the four borders of the heart and what do they contain?

Answer 26

right border- right atrium, left border- left ventricle, inferior border- left and right ventricle, superior border- right and left atrium and the great vessels

Question 27

What are the grooves on the surface of the heart called?

Answer 27

sulci

Question 28

What are the main sulci of the heart and where do they run?

Answer 28

the coronary sulcus- runs transversely around the heart and contains the right coronary artery
the anterio and posterior interventricular sulci- can be found running vertically on their respective sides of the heart

Question 29

which nerve is responsible for the somatic innervation of the pericardium?

Answer 29

phrenic nerve

Question 30

On a Chest X-ray which parts of the heart should be visible?

Answer 30

left border (left ventricle and some of the left atrium) and the right border (right atria). Also the left auricular appendage

Question 31

where the pain be referred to if there was painful stimulation of the diaphragm?

Answer 31

side of the neck and the shoulder tip. this is because the diaphragm is innervated by the phrenic nerve with nerve roots C3, C4 and C5 which originates in the neck..

Question 32

If fluid collects in the pericardium (pericardial effusion) what will the consequences be to heart function?

Answer 32

the pericardium becomes rigid and cannot expand therefore the heart is subject to increased pressure therefore there is limited ventricular and chamber filling which will reduce cardiac output.

Question 33

what is the transverse sinus?

Answer 33

formed by the way in which the pericardium folds around the great vessels, and is a passageway through the pericardial cavity

Question 34

What is pericarditis?

Answer 34

inflammation of the pericardium

Question 35

Where would you place a needle to remove fluid or blood from the pericardial cavity?

Answer 35

into the angle between the xiphoid process and left seventh costal cartilage, directed upwards 45 degrees towards left shoulder.
This is because the pericardial cavity is closest to the surface at the level of the xiphoid process and 6th costal cartilage.