superior mediastinum

Question 1

what is the mediastinum

Answer 1

midline partition that separates thee pleural cavities

Question 2

where is the mediastinum

Answer 2

from the superior thoracic aperture to inferior thoracic aperture
between sternum anteriorly and thoracic vertebrae posteriorly

Question 3

what happens at the superior thoracic cavity

Answer 3

airways enter and vein drains back to the heart

Question 4

what is the role of the mediastinum

Answer 4

acts as a conduit for structures that pass through thorax and structures that connect thoracic organs to other body structures
2 way conduit - head and neck to chest cavity and in reverse
airway from superior to carina to lungs pharynx opening in nasal cavities through thorax and to abdomen, nerve control heart and lung from brain into pericardium and airways

Question 5

what does a PA x ray mean

Answer 5

x ray go through back of body and detector is at the front

Question 6

why is a PA x ray done

Answer 6

PA/AP give different size of organs
heart is anterior - if PA short distance to detector - little dispersion
if AP - big distance to detector= large dispersion

Question 7

components of the mediastinum

Answer 7

trachea - C6-T4/5 from larynx to bifurcation into principle bronchi
oesophagus - from pharynx, muscular tube, pierce diaphragm T10
heart and pericardium
thoracic duct - lymphatic drainage (remove interstitial fluid and involved in metastatic disease)
nerves and great vessels

Question 8

what is the larynx

Answer 8

air way in throat

Question 9

what structures pass through the diaphragm and where

Answer 9

T8 - inf V C
10 - oesophagus
12 - aorta

Question 10

what do 8 10 12 relate to in the chest

Answer 10

pleural cavity

Question 11

what does 6 8 10 levels relate to in the chest

Answer 11

level lungs

Question 12

where is the superior mediastinum

Answer 12

above sternal angle

from superior thoracic aperture

Question 13

where is the inferior mediastinum

Answer 13

below sternal angle

above inferior thoracic aperture

Question 14

what 3 parts make up the inferior mediastinum

Answer 14

middle
anterior
posterior

Question 15

middle mediastinum

Answer 15

has pericardial sac and heart

Question 16

anterior mediastinum

Answer 16

anterior to heart

small

Question 17

posterior mediastinum

Answer 17

behind pericardial sac and diaphragm
has nerves of SNS and veins that drain chest from abdomen to heart
has everything that moves from superior to inferior

Question 18

what are the contents of the superior mediastinum

Answer 18

thymus - immunologically active, replaced by fat 
phrenic nerves - contract diaphragm and provide sensation for pericardium and peritoneal lining (under diaphragm)
great veins 
main lymphatic trunk 
vagus nerves
great arteries
trachea and main  bronchi 
upper oesophagus

Question 19

what are the great veins

Answer 19

superior vena cava (enter RA from above)

inferior vena cava (enter RA from below - through the central tendon of diaphragm T8!)

Question 20

describe the superior vena cava in situ

Answer 20

offset to the R
formed by the union of R and L brachiocephalic veins
brachiocephalic vein forms internal jugular veins (drain head) and subclavian veins (drain arms)

Question 21

what is the path of the L brachiocephalic vein

Answer 21

crosses at sternoclavicular joint, and manubrium and 1st rib posterior to manubrium to reach R brachiocephalic vein to form the SVC
the veins move anterior to the arteries

Question 22

describe the azygous vein

Answer 22

asymmetric
largest on R
anterior intercostal vessels drained into internal thoracic vessels
drains posterior wall of thorax and abdomen
hemiazygos and accessory hemiazygos on L - drain chest wall
arches over the R lung root
runs behind SVC carrying deoxygenated blood
drains into the superior VC

Question 23

inferior vena cava in situ

Answer 23

little in thorax
goes straight into the RA
most is in the abdomen

Question 24

where does the L superior intercostal vein drain into

Answer 24

brachiocephalic vein

Question 25

arteries in superior mediastinum

Answer 25

ascending aorta - come superior from the heart arch of aorta - move superiorly, laterally and down descending aorta - down back, diaphragm and to abdomen at T12

Question 26

ascending aorta

Answer 26

R and L coronary arteries supply heart muscle with the most oxygenated blood terminal arteries may need bypass (from leg vein)

Question 27

aortic arch

Answer 27

brachiocephalic trunk - R common carotid and R subclavian arteries L common carotid L subclavian artery - under clavical - to axilla and upper limbs

Question 28

relation of aortic arch to pulmonary branch

Answer 28

anterior

Question 29

relation of aorta nad arteries to airways

Answer 29

aortic arch anterior to trachea arches over L main bronchus at lung root trachea is behind and between the brachiocephalic and L common carotid arteries azygous vein runs along the back of the chest - arch over airways over lung root into back of superior vena cava

Question 30

explanation of the points components pass through diaphragm

Answer 30

aorta almost vertical at the back - pass more posteriorly and so at a lower vertebral level than oesophagus and IVC then oesophagus than IVC

Question 31

distribution of the common carotid arteries

Answer 31

divide into internal and external carotids high in the neck at laryngeal prominence they are the main arteries of the head and neck - with vertebral arteries from subclavian arteries) internal supply brain

Question 32

pulmonary trunk

Answer 32

outflow of the R ventricle deox blood via L and R pul arteries to the lungs 1st travels backwards behind the arch - emerge to L of aorta from RV

Question 33

when listen to aorta you listen

Answer 33

to R of sternum

Question 34

when listen to pulmonary artery you listen

Answer 34

L of sternum

Question 35

pulmonary trunk

Answer 35

from RV deox blood to lung divide into L and R pul arteries

Question 36

describe the remnant of fetal circulation in the pulmonary trunk

Answer 36

remnant of the ductus arteriosus - vessel from pul trunk to aorta to bypass lungs - blood into the systemic system this closes off - forms ligamentum arteriosum

Question 37

where are the phrenic nerves formed

Answer 37

in cervical p5 plexus - C3, 4 5

Question 38

what do the phrenic nerves do

Answer 38

they are motor to the diaphragm sensory to- central tendon of diaphragm, mediastinal pleura, pericardium, peritoneum of central diaphragm - innervate underside of the diaphragm

Question 39

C3 4 5 …. (rhyme)

Answer 39

keeps diaphragm alive

Question 40

what does the R phrenic nergve lie on top of to reach the diaphragm

Answer 40

R brachiocephalic vein SVC R side of heart and pericardium - in front of the lung root

Question 41

what is the effect of damage to the laryngeal nerves

Answer 41

change voice | need to know about the difference in length

Question 42

why is the point of the ligamentum arteriosum anatomically important

Answer 42

nerves emerging from neck winds round here and goes back towards the neck from vagus nerve 2 small branches - recurrent laryngeal nerves, 1 winds round here other around R subclavian artery on the R side discrepancy in length

Question 43

describe the relations of the great arteries to main nerves

Answer 43

vagus nerves are lateral to the common carotid left vagus - anterior to the aortic arch left phrenic crosses vagus to cross the aortic arch anteriorly vagus is behind the lung root R phrenic is in front of the lung, runs right next to the SVC - down pericardium through diaphragm - innervates other side

Question 44

describe the path of the left phrenic and vagus nerves

Answer 44

cross arch of aorta left phrenic decends in front of lung root L vagus - behind the lung root - gives off L recurrent laryngeal nerve - recurs around ligamentum arteriosum and aortic arch break into many branches round oesophagus forms oesophageal nerve and through diaphragm at T10 with oesophagus

Question 45

path of the R vagus nerve

Answer 45

lies on the trachea crosses behind the root lung recurrent laryngeal branch recurs around R subclavian artery breaks up into branches on the oesophagus