superior mediastinum

Question 1

what does the mediastinum separate

Answer 1

both pleural cavities

Question 2

where does the mediastinum extend from and to (superior to posterior)

Answer 2

superior thoracic aperture (inlet) to inferior thoracic aperture

Question 3

where does the mediastinum extend from and to (anterior to posterior)

Answer 3

between sternum anteriorly and thoracic vertebrae posteriorly

Question 4

what does the mediastinum act as

Answer 4

conduit for structures that pass through thorax and for structures that connect thoracic organs to other body regions

Question 5

what are the 6 principal contents of the mediastinum

Answer 5

trachea, oesophagus, heart and pericardium, thoracic duct, nerves, great vessels

Question 6

where does the trachea extend from and to

Answer 6

from larynx to bifurcation into principal bronchi (C6 to T4/5)

Question 7

where does the oesophagus extend from and to

Answer 7

from pharynx to diaphragm at level T10

Question 8

what is the purpose of the thoracic duct

Answer 8

lymphatic drainage

Question 9

what are the 5 divisions of the mediastinum

Answer 9

superior (above sternal angle), inferior (below sternal angle), anterior (anterior to heart in pericardial sac), middle (pericardial sac and heart), posterior (posterior to pericardial sac and diaphragm)

Question 10

diagram of 5 divisions of the mediastinum (mid-saggital view)

Answer 10

slide 5

Question 11

contents (8) of superior mediastinum from anterior to posterior

Answer 11

thymus, phrenic nerves, great veins, main lymphatic trunks, vagus nerve, great arteries, trachea and main bronchi, upper oesophagus

Question 12

what are the two great veins

Answer 12

superior vena cava and inferior vena cava

Question 13

what does the superior vena cava enter and from where

Answer 13

right atrium from above, to right of aorta

Question 14

what does the inferior vena cava enter, from where and through what

Answer 14

right atrium from below through central tendon of diaphragm at T8 (where heart sits)

Question 15

what is the superior vena cava formed by

Answer 15

asymmetric union of right and left brachiocephalic veins (left crosses to join right)

Question 16

what does each brachiocephalic vein (arm and head) form from

Answer 16

an internal jugular vein and a subclavian vein

Question 17

what tributaries form left and right brachiocephalic veins and from where

Answer 17

internal jugular vein (from head) and subclavian veins (from upper limbs)

Question 18

where does the left brachiocephalic vein cross to join right brachiocephalic vein

Answer 18

crosses posterior to and to the right of manubrium (sternum)

Question 19

what is the function of the azygos vein

Answer 19

drain posterior wall of thorax and abdomen into superior vena cava

Question 20

what does the azygos vein arch over

Answer 20

right lung root (asymmetric as right is more prominent)

Question 21

what are the 3 parts of the aorta of the superior mediastinum

Answer 21

ascending aorta, arch of aorta, descending aorta (T12)

Question 22

what are the 2 branches of the ascending aorta

Answer 22

right and left coronary arteries (first as supply heart with most richly oxygenated blood; end arteries)

Question 23

what are the 3 branches of the aortic arch

Answer 23

brachiocephalic trunk, left common carotid artery, left subclavian artery

Question 24

what does the brachiocephalic trunk divide into

Answer 24

right common carotid and right subclavian arteries

Question 25

where does the aortic arch arise in relation to the trachea

Answer 25

anteriorly

Question 26

what does the aortic arch arch over

Answer 26

left main bronchus at lung root

Question 27

what arteries does trachea lie behind and between

Answer 27

brachiocephalic and left common carotid arteries

Question 28

what are common carotid arteries divided into and where

Answer 28

external and internal carotids high in neck

Question 29

what is the function of the carotid arteries

Answer 29

supply head (face and brain) and neck

Question 30

what arteries do the vertebral arteries (neck) come from

Answer 30

subclavian arteries

Question 31

what is the outflow of the right ventricle

Answer 31

pulmonary trunk

Question 32

what does the pulmonary trunk carry, via what and where to

Answer 32

deoxygenated blood via left and right pulmonary arteries to lungs; to left of aorta

Question 33

what connects the pulmonary trunk to the aortic arch

Answer 33

ligamentum arteriosum

Question 34

what is the ligamentum arteriosum a remnant of

Answer 34

ductus arteriosus (bypasses lungs in foetal life - becomes 'ligament' when born)

Question 35

what are phrenic nerves formed in

Answer 35

cervical plexus from C3, C4 and C5

Question 36

what do motor phrenic nerves innovate

Answer 36

diaphragm

Question 37

what 4 structures do sensory phrenic nerves innovate

Answer 37

central tendon to diaphragm, mediastinal pleura, pericardium, peritoneum of central diaphragm

Question 38

what phrenic nerve reaches diaphragm

Answer 38

right and left separately

Question 39

what 3 structures does the right phrenic nerve lie on the surface of

Answer 39

right brachiocephalic vein, superior vena cava, right side of heart and pericardium in front of lung root

Question 40

where do vagus nerves lie in relation to common carotids

Answer 40

lateral

Question 41

where does left vagus pass in relation to aortic arch

Answer 41

anterior

Question 42

where does left phrenic cross the vagus in relation to aortic arch

Answer 42

more anteriorly

Question 43

where does left phrenic descend

Answer 43

in front of root lung

Question 44

where does left vagus cross in relation to root lung

Answer 44

behind

Question 45

what does left vagus give off

Answer 45

left recurrent laryngeal nerve

Question 46

where does the left recurrent laryngeal nerve recur around

Answer 46

ligamentum arteriosum and aortic arch

Question 47

where does the left recurrent laryngeal nerve break up into many branches

Answer 47

round oesophagus

Question 48

where does the right vagus nerve lie

Answer 48

on trachea

Question 49

where does right vagus cross in relation to root lung

Answer 49

behind

Question 50

what does right vagus give off

Answer 50

right recurrent laryngeal nerve

Question 51

where does the right recurrent laryngeal nerve recur around

Answer 51

right subclavian artery

Question 52

where does the right recurrent laryngeal nerve break up into many branches

Answer 52

round oesophagus

Question 53

AP vs PA x-ray

Answer 53

always coronal, but depends on which direction x-ray shone (can tell by determining whether posterior or anterior of rib is more prominent) - gives different sizes to structures of interest as x-rays travel and spread further before detector - different views of dimension

Question 54

T8, 10, 12

Answer 54

IVC, oesophagus, descending aorta structure into diaphragm

Question 55

T6, 8, 10

Answer 55

level of lungs (T10 is start of abdomen)