Superior mediastinum

Question 1

what is the mediastinum?

Answer 1

the central compartment of the thoracic cavity

Question 2

where is the mediastinum located?

Answer 2

between the 2 pleural sacs

Question 3

what does the mediastinum contain?

Answer 3

most of the thoracic organs

Question 4

what does the mediastinum act as?

Answer 4

a conduit for structures traversing the thorax on their way into the abdomen

Question 5

how is the mediastinum divided anatomically?

Answer 5

into 2 parts by an imaginary line that runs from the sternal angle to the T4 vertebrae

Question 6

what is the sternal angle?

Answer 6

the angle formed by the junction of the sternal body and manubrium

Question 7

where does the superior mediastinum extend? where does it terminate?

Answer 7

extends upwards

terminating at the superior thoracic aperture

Question 8

where does the inferior mediastinum extend? where does it terminate?

Answer 8

downwards

terminating at the diaphragm

Question 9

what is the inferior mediastinum further subdivided into?

Answer 9

anterior mediastinum
middle mediastinum
posterior mediastinum

Question 10

what is the superior mediastinum’s superior border?

Answer 10

thoracic inlet

Question 11

what is the superior mediastinum’s inferior border?

Answer 11

continuous with the inferior mediastinum at the level of the sternal angle

Question 12

what is the superior mediastinum’s anterior border?

Answer 12

manubrium of the sternum

Question 13

what is the superior mediastinum’s posterior border?

Answer 13

vertebral bodies of T1-4

Question 14

what is the superior mediastinum’s lateral border?

Answer 14

pleurae of the lungs

Question 15

what are the contents of the superior mediastinum anatomical area?

Answer 15

neural, vascular, respiratory structures

passing from adjacent regions of the neck and abdomen (via inferior mediastinum)

Question 16

what are the great vessels through run through the superior mediastinum?

Answer 16

the great systemic blood vessels of the heart and it’s main branches arise in SM before passing through the superior thoracic aperture

Question 17

which branches of the aortic arch arise within the superior mediastinum?

Answer 17

brachiocephalic artery
left common carotid artery
left subclavian artery

Question 18

what does the brachiocephalic artery supply?

Answer 18

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

Question 19

where does the left common carotid artery travel to?

Answer 19

to the left side of the head and neck

Question 20

where does the left subclavian artery travel to?

Answer 20

left upper limb

Question 21

what are tributaries of the superior vena cava and where are they located?

Answer 21

in the superior mediastinum:
brachiocephalic veins
left superior intercostal vein
supreme intercostal vein
azygos vein

Question 22

what does the Brachiocephalic vein drain?

Answer 22

draining blood from the upper body

Question 23

what does the Left superior intercostal vein collect?

Answer 23

collects blood from the left 2nd and 3rd intercostal vein

Question 24

where does the left superior intercostal vein drain into?

Answer 24

the left brachiocephalic vein

Question 25

where does the supreme intercostal vein drain from and to?

Answer 25

drains the vein from first intercostal space directly into the brachiocephalic veins

Question 26

where does the azygos vein receive blood from?

Answer 26

the right posterior intercostal veins

Question 27

where do the left intercostal veins drain first into?

Answer 27

The left intercostal veins drain first into the hemiazygos and accessory hemiazygos veins

Question 28

what happens after the left intercostal veins have drained into the hemiazygos and accessory hemiazygos veins?

Answer 28

joins the azygos vein around T7-T9

Question 29

what is the path of the right vagus nerve within the superior mediastinum?

Answer 29

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

Question 30

where does the left vagus nerve enter the superior mediastinum?

Answer 30

between the left common carotid and the left subclavian arteries

Question 31

what is the path of the left vagus nerve within the superior mediastinum?

Answer 31

It descends anteriorly to the aortic arch, before travelling posterior to the left bronchus

Question 32

where does the left recurrent laryngeal nerve arise from?

Answer 32

the left vagus nerve as it passes the aortic arch

Question 33

what is the course of travel of the left recurrent laryngeal nerve?

Answer 33

It loops under the aortic arch, to the left of ligamentum arteriosum, before continuing its journey to the larynx in the tracheal-oesophageal groove

Question 34

where does the phrenic nerve enter the superior mediastinum?

Answer 34

From the anterior surface of the anterior scalene muscle, the phrenic nerves enter the superior mediastinum lateral to the great vessels

Question 35

what is the course of travel of the phrenic nerve within the superior mediastinum?

Answer 35

They then descend anteriorly into the middle mediastinum, passing anteriorly to the hilum of the lungs

Question 36

what are the nerve roots of the phrenic nerve?

Answer 36

C3, C4, C5

Question 37

where does the cardiac nerves originate from?

Answer 37

the superior, middle and inferior cardiac ganglion and form the superficial and deep cardiac plexuses in the superior mediastinum

Question 38

where does the superior plexus sit?

Answer 38

between the aortic arch and right pulmonary vein

Question 39

where does the deep plexus lie?

Answer 39

on the surface of the trachea at the point of bifurcation

Question 40

where does the sympathetic trunk run?

Answer 40

bilaterally to the vertebral bodies along the entire length of the vertebral column

Question 41

what are the other structures present in the superior mediastinum?

Answer 41

thymus trachea thoracic duct muscles

Question 42

which structure is the most anterior within the superior mediastinum?

Answer 42

The thymus gland

Question 43

where is the thymus gland situated?

Answer 43

It sits flush against the posterior surface of the sternum and extends into the anterior mediastinum and can often reach into the neck

Question 44

what does the trachea bifurcate into? where?

Answer 44

the primary bronchi posterior to the ascending aorta at the level of the sternal angle

Question 45

what is the course of travel of the thoracic duct within the superior mediastinum?

Answer 45

the thoracic duct passes to the left of the oesophagus on its path to the junction of the left internal jugular and subclavian veins

Question 46

which muscles originate from the posterior surface of the manubrium?

Answer 46

The infrahyoid muscles, sternohyoid and sternothyroid

Question 47

what else originates within the inferior aspects of the superior mediastinum?

Answer 47

The inferior aspects of the longus colli