Thorax 9: Posterior Mediastinum

Question 1

What vertebral levels define the posterior mediastinum?

Answer 1

T4/5 and posterior attachment of the diaphragm at T12

Question 2

what are the levels that define the thoracic aorta?

Answer 2

from T4/5/angle of louis at 2nd costal cartilage to the aortic hiatus at T12

Question 3

how does the thoracic aorta pass through the diaphragm

Answer 3

runs between the crura and behind the median arcuate ligament

Question 4

define the relationship of the thoracic aorta to the vertebral bodies

Answer 4

initially lies on the left of vertebral bodies

moves to midline in lower thorax

Question 5

Name the branches of the aorta

Answer 5

posterior intercostal arteries
bronchial arteries
oesophageal arteries
subcostal arteries
small branches to diaphragm and pericardium

Question 6

how many posterior intercostal arteries are there and what do they supply?

Answer 6

9 arteries that supply lower 9 intercostal spaces from ribs 3-11

Question 7

what artery supplies the first 2 intercostal spaces and what does it arise from

Answer 7

superior intercostal artery arising from the costocervical trunk of the subclavian arteries

Question 8

where do the anterior intercostals arise from?

Answer 8

internal thoracic arteries arising from the subclavian arteries

Question 9

how many bronchial arteries are there?

Answer 9

2 left and 1 right

Question 10

what part of the oesophagus is supplied by the thoracic aorta?

Answer 10

middle 1/3 of the oesophagus

Question 11

what drains the part of the oesophagus supplied by the thoracic aorta?

Answer 11

azygous vein

Question 12

what artery supplies the posterior abdominal wall

Answer 12

subcostal arteries that lie inferior to the 12th rib

Question 13

what is the vascular supply of the superior 1/3 of the oesophagus

Answer 13

arterial from inferior thyroid arteries

venous to brachiocephalic veins

Question 14

what is the nervous supply of the superior 1/3 of the oesophagus?

Answer 14

recurrent laryngeal nerves of the vagus nerve

Question 15

the deep cervical nodes drain which part of the oesophagus?

Answer 15

superior 1/3

Question 16

what part of the oesophagus is made up of striated muscle only

Answer 16

superior 1/3

Question 17

which part of the oesophagus is made up of mixed muscle

Answer 17

middle 1/3

Question 18

what part of the oesophagus is supplied by the oesophageal plexus?

Answer 18

middle and inferior 1/3s

Question 19

the tracheobronchial nerves drain which part of the oesophagus?

Answer 19

middle 1/3

Question 20

what is the vascular supply of the inferior 1/3 of the oesophagus

Answer 20

arterial - left gastric artery

venous - left gastric vein and portal vein

Question 21

what is the lymphatic drainage of the inferior 1/3 of the oesophagus?

Answer 21

coeliac nodes

Question 22

what are the relationships of the oesophagus in the superior mediastinum?

Answer 22

posterior to trachea

right of the aorta

Question 23

what are the relationships in the inferior mediastinum of the oesophagus?

Answer 23

swings forward and to the left
anterior to the aorta
leaves at T10

Question 24

what forms the cardiac sphincter?

Answer 24

the oblique entry of the oesophagus into the stomach
resting tone of smooth muscle
prevents gastric reflux

Question 25

what is significant about the submucosal veins

Answer 25

form an anastomoses between the venous drainage of the lower and middle 1/3s connects the portal and systemic circulations

Question 26

what is the distance to the upper oesophageal sphincter and what is the anatomical landmark

Answer 26

17cm | junction of oesophagus with pharynx

Question 27

name the 4 oesophageal sphincters

Answer 27

upper oesophageal sphincter arch of the aorta left main bronchus lower oesophageal sphincters

Question 28

what is the distance to the 3rd oesophageal sphincter

Answer 28

28 cm

Question 29

what is the distance to the last oesophageal sphincter

Answer 29

43 cm

Question 30

what problems are caused by the oesophageal sphincters

Answer 30

blockage more likely passage of instruments more difficult slow down passage of caustic substances

Question 31

what is found posterior to the oesophagus

Answer 31

thoracic duct and thoracic aorta inferiorly

Question 32

at what point does the thoracic duct cross the oesophagus

Answer 32

T4/5

Question 33

where does the thoracic duct receive lymph from?

Answer 33

left jugular lymph trunk of head and neck subclavian lymph trunk of upper limb bronchomediastinal trunk of left thorax

Question 34

where are posterior mediastinal nodes found

Answer 34

behind the heart near the oesophagus

Question 35

describe the route of lymph from pulmonary nodes

Answer 35

bronchopulmonary - inferior and superior tracheobronchial - paratrancheal - bronchomediastinal lymph trunks

Question 36

describe the route of lymph from the posterior mediastinal nodes

Answer 36

paratracheal - bronchomediastinal

Question 37

which node groups drain straight into the bronchomediastinal trunks

Answer 37

parasternal/internal thoracic | anterior mediastinal

Question 38

what does the azygous vein drain

Answer 38

posterior thorax wall

Question 39

where does the azygous vein begin?

Answer 39

begins from the lumbar and subcostal veins or a direct branch of the IVC

Question 40

where does the azygous vein lie on the vertebral column?

Answer 40

midline or to the right

Question 41

where does the azygous vein join the SVC

Answer 41

2nd right costal cartilage

Question 42

what vessels does the azygous vein receive?

Answer 42

veins equivalent to branches of the descending thoracic aorta

Question 43

what are the parts of the hemiazygous veins

Answer 43

lower and upper accessory hemiazygous veins

Question 44

what is the route of the lower hemiazygous vein

Answer 44

connects with left renal vein passes through or behind left crus of diaphragm crosses to azygous at T9

Question 45

what is the route of the upper accessory hemiazygous vein?

Answer 45

descend from the 4th intercostal space and crosses to azygous at T8

Question 46

what can cause pain on swallowing

Answer 46

oesophageal indentations caused by arthritic osteophytes

Question 47

what causes portal hypertension

Answer 47

cirrhotic liver disease

Question 48

what causes oesophageal varices

Answer 48

escaping of blood from portal vein to azygous vein via the submucosal portosystemic anastomosesin portal hypertension

Question 49

what is a danger of thoracic surgery

Answer 49

damage to thoracic duct leakage of lymph chylothorax