The Superior Mediastinum

Question 1

What is the mediastinum?

Answer 1

Central compartment of thorax, located between pleural sacs

Question 2

The superior mediastinum extends upwards from the________

Answer 2

sternal angle (level of T4 vertebrae)

Question 3

Where does the superior mediastinum terminate?

Answer 3

superior thoracic aperture

Question 4

The inferior mediastinum extends downwards from the _________

Answer 4

sternal angle (level of T4 vertebrae)

Question 5

Where does the inferior mediastinum terminate?

Answer 5

diaphragm

Question 6

Which three major branches of the aortic arch arise in the superior mediastinum?

Answer 6

brachiocephalic artery, left common carotid artery, left subclavian artery

Question 7

What does the brachiocephalic artery supply?

Answer 7

right side of head and neck, right upper limb

Question 8

what does the left common carotid artery supply?

Answer 8

left side of head and neck

Question 9

what does the left subclavian artery supply?

Answer 9

left upper limb

Question 10

Which tributaries of the superior vena cava are found in the superior mediastinum?

Answer 10

brachiocephalic veins(left and right), left superior intercostal vein, supreme intercostal vein, azygous vein

Question 11

What vessels drain into the left superior intercostal vein?

Answer 11

left 2nd and 3rd intercostal veins

Question 12

Which vein drains into the supreme intercostal vein?

Answer 12

the vein from the first intercostal space

Question 13

Where does the azygous vein receive blood from?

Answer 13

the right posterior intercostal veins. The left intercostal veins drain first into the hemiazygos and accessory hemiazygos veins before joining the azygos vein around T7-T9.

Question 14

Which major nerves are located in the superior mediastinum?

Answer 14

Left and right vagus nerve, phrenic nerve, cardiac nerves, sympathetic trunk

Question 15

What is the path of the left vagus nerve?

Answer 15

It 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 is the path of the right vagus nerve?

Answer 16

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

Question 17

Which nerve arises from the left vagus nerve and loops under the aortic arch?

Answer 17

left recurrent laryngeal nerve

Question 18

Where does the phrenic nerve enter the superior mediastinum?

Answer 18

anterior surface of anterior scalene muscle, lateral to great vessels. then descend anteriorly

Question 19

Which nerve forms superficial and deep cardiac plexuses in superior mediastinum?

Answer 19

cardiac nerves

Question 20

Where does the superior plexus sit?

Answer 20

between the aortic arch and right pulmonary vein

Question 21

Where does the inferior plexus sit?

Answer 21

on the surface of the trachea at the point of bifurcation

Question 22

What is the route of the sympathetic trunk?

Answer 22

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

Question 23

What other structures are found in the superior mediastinum?

Answer 23

thymus, trachea, oesophagus, thoracic duct, muscles