Anterior and Superior Mediastinum

Question 1

What are the boundaries of the Anterior Mediastinum?

Answer 1

between the sternum and the pericardium

Question 2

What are the boundaries of the Superior mediastinum?

Answer 2

• between the thoracic inlet and the sternal angle at level T4/5
• posterior to the manubrium of the sternum
• anterior to T1- T4
• oblique from manubrium upwards to T1

Question 3

Which structure lies in the anterior mediastinum?

Answer 3

thymus

Question 4

Where is the thymus situated?

Answer 4

from the jugular notch to the 4th costal cartilage

Question 5

What is its structure and function?

Answer 5

• bi-lobed

- T lymphocytes and recognition of self

Question 6

What are the anatomical relations of the thymus?

Answer 6

• SVC and Aorta
• L+R Brachiocephalic veins
• pleura, phrenic nerves, trachea

Question 7

What is the blood supply and venous drainage of the thymus?

Answer 7

• internal thoracic and inferior thyroid arteries

- left brachiocephalic vein

Question 8

What are structures on the right of the mediastinum associated to?

Answer 8

veins and the right atrium of the heart

Question 9

Which nerve runs with the trachea in the R Superior mediastinum?

Answer 9

R vagus nerve

Question 10

What structure does the Right phrenic nerve run with in the Right superior mediastinum?

Answer 10

SVC

Question 11

Which nerve runs with the aortic arch?

Answer 11

left vagus nerve

Question 12

Which structure is the left phrenic nerve associated in the left superior mediastinum?

Answer 12

left ventricle of heart

Question 13

What are the 3 planes of the superior mediastinum from most anterior to posterior?

Answer 13

• venous
• arterial
• trachea and oesophagus

Question 14

What does the SVC divide into superiorly?

Answer 14

Left and right brachiocephalic veins

Question 15

what are the branches of the L+R BCVs and which is medial?

Answer 15

• L+R internal Jugular vein, medially,

- L+R subclavian veins, laterally

Question 16

What is the anatomical position of the bifurcation of the SVC to the L+R BCVs?

Answer 16

posterior to the 1st right costal cartilage

Question 17

Where, anatomically, does the arch of the Azygous vein join the SVC?

Answer 17

posterior to the 2nd right costal cartilage

Question 18

Where anatomically does the SVC enter the right atrium?

Answer 18

posterior to the 3rd right costal cartilage

Question 19

Where does the azygous vein drain?

Answer 19

posterior chest wall

Question 20

Where does the subclavian vein drain?

Answer 20

the upper limb

Question 21

what are the internal jugular veins responsible for draining?

Answer 21

head and neck

Question 22

Which veins drain into the Left BCV?

Answer 22

• veins from anterior chest wall

- internal thoracic arteries

Question 23

Which surgical procedure are thyroid veins at risk and why?

Answer 23

• drain into the LBCV, mainly in children they protrude above manubrium
• hence are at risk during tracheotomy

Question 24

How are the vagus nerves related to the BCVs?

Answer 24

R+L vagus nerves are medial to the R+L BCVs

Question 25

How are the R+L phrenic nerves related to the BCVs?

Answer 25

lateral to the R+L BCVs

Question 26

What are the 3 branches of the aortic arch from right to left?

Answer 26

- brachiocephalic trunk (BCT) - left common carotid artery - left subclavian artery

Question 27

what level is the arch situated at?

Answer 27

T4/5

Question 28

Where anatomically does the BCT divide and what structures does it give?

Answer 28

- posterior to right sternoclavicular joint | - R subclavian and R common carotid

Question 29

where is left subclavian vein anatomically situated?

Answer 29

posterior and L of the trachea

Question 30

Which vessels do the R and L vagus nerves relate to?

Answer 30

- R vagus nerve is anterior to the R subclavian artery | - L vagus nerve is lateral to the L common carotid artery

Question 31

Which 2 nerves relate to the arch of the aorta and how?

Answer 31

L vagus nerve and L phrenic nerve lateral to the arch

Question 32

What level does the Trachea start from and extend to?

Answer 32

- starts at C6 | - Carina (bifurcation to L+R main bronchi) at T4/5

Question 33

Which muscle alters tracheal diameter? Where is it located?

Answer 33

- trachealis posterior | - posterior between the ends of the C shaped cartilage rings

Question 34

How is it associated with the oesophagus? which nerves associated with the trachea and the oesophagus?

Answer 34

trachea is anterior to the oesophagus and the left recurrent laryngeal nerve in-between

Question 35

How does the right main bronchus differ from the left?

Answer 35

- wider - shorter - more vertical than the left

Question 36

What alters tracheal diameter at rest?

Answer 36

smooth muscle contraction

Question 37

What is the function of the oesophagus?

Answer 37

transport of food and fluid through the thorax and diaphragm into the stomach

Question 38

What is the anatomical position of the oesophagus?

Answer 38

- starts at C6 - passes immediately posterior to trachea and anterior to vertebral column - aortic arch is anterior on the left

Question 39

What is the function of the thoracic duct? What is it a continuation of?

Answer 39

- lymphatic efferents from the rest of the body empty into the thoracic duct - cisterna chyli

Question 40

Which structures does it lie between? What level does it cross to the left side of the body?

Answer 40

- thoracic (descending) aorta and azygous vein | - T4/5

Question 41

Which vein does the thoracic duct drain into?

Answer 41

the left brachiocephalic vein at the junction of the L IJV and LScV

Question 42

Which nodes do the nodes of the lung and the lung hilum drain into? Where are these nodes located

Answer 42

- mediastinal nodes | - clustered around trachea and oesophagus

Question 43

Which nodes lie superior and inferior to the tracheal bifurcation?

Answer 43

superior and inferior tracheobronchial nodes

Question 44

Which vessels do the anterior nodes lie around?

Answer 44

around the brachiocephalic veins

Question 45

Which of 2 structures do all nodes drain into?

Answer 45

- thoracic duct on the right | - communicate with deep cervical nodes

Question 46

how are lymph nodes clinically relevant?

Answer 46

may be involved in the spread of tumour

Question 47

What structure in the superior mediastinum can lung tumours affect?

Answer 47

the larynx causing a hoarse voice

Question 48

Which nodes can become palpable with a lung tumour?

Answer 48

lymph nodes in neck