Thoracic Cavity 2

Question 1

Describe the location of the trachea and what levels the carina moves to during respiration

Answer 1

The trachea starts at C6 vertebra and ends at the bifurcation at the carina (T4). During respiration the carina can move to as low as T6 and high as T4

Question 2

what are the landmarks in the superior mediastinum?

Answer 2

1- posterior to the sternoclavicular joint
2- posterior to 1st right cc
3- posterior to the 2nd right cc
4- posterior to the 3rd right cc

Question 3

what would you expect to see in the posterior mediastinum?

Answer 3

• vertebral bodies
• proximal costal segments
• proximal segments of posterior intercostal vessels
• proximal segments of intercostal nerves
• sympathetic chain with its ganglia

Question 4

At the level of T3, what structures are viable in a transverse plane?

Answer 4

The brachiocephalic trunk, left common carotid, left subclavian, the brachiocephalic veins and trachea, oesophagus, nerves ect.

Question 5

At the level of T4 what are the structures visable in z transverse plane?

Answer 5

Aortic arch, SVC, arch of azygos, trachea, oesophagus and nerves

Question 6

What is posterior to the sternoclavicular joint?

Answer 6

v - Formation of brachiocephalic veins from the internal jugular and subclavian vein.
a - Division of the brachiocephalic trunk into right common carotid and right subclavian a.

Question 7

describe the thoracic aorta?

Answer 7

• distal continuation of the aortic arch
• between the level of sternal angle and aortic hiatus (T12)
• lies on the left of the thoracic vertebral bodies, but moves to the midline in the lower thorax.

Question 8

What is posterior to the 1st right costal cartilage?

Answer 8

Formation of superior vena cava from the right and left brachiocephalic veins

Question 9

What is posterior to the 2nd right costal cartilage

Answer 9

Arch of azygos vein joins SVC

Question 10

What is posterior to the 3rd right costal cartilage?

Answer 10

SVC enters right atrium

Question 11

What is the posterior wall of the posterior mediastinum made up of?

Answer 11

Vertebral bodies, Posterior costal segments, Proximal segments posterior IC vessels, Proximal segments of IC nerves, and the sympathetic chain with ganglia.

Question 12

Describe how the thoracic aorta forms the abdominal aorta

Answer 12

At the sternal angle the thoracic aorta forms, it lies to the left of thoracic vertebrae but move to the midline in lower thorax. It passes through the diagram behind the oesophagus at T12

Question 13

What are the visceral branches of the thoracic aorta?

Answer 13

These supply the organs of mediastinum:
Osophageal arteries,
Bronchial arteries,
Pericardial branches, 
Mediastinal branches and superior phrenic artery (classes as parietal as well)

Question 14

What are the parietal branches of the thoracic aorta?

Answer 14

Posterior intercostal arteries, subcostal arteries and (superior phrenic artery)

Question 15

Where does the oesophagus start and peirce the diaphragm?

Answer 15

Starts at C6, descends between vertebral column and trachea then pierces the diaphragm at T10

Question 16

Describe what type of muscle is the oesophagus made up off?

Answer 16

Upper 1/3 - straited and voluntary.
Middle 1/3rd is mix of smooth and striated. Lower 1/3rd is smooth
Stratified squamous epithelium

Question 17

Name the 4 constrictions of the oesophagus

Answer 17

Upper oesophageal sphincter, where it is crossed by arch of aorta, where is is compressed by the left main bronchus and at the diaphragm. (left atrium causes narrowing)

Question 18

What is are the clinical significance of the 4 oesophageal constrictions?

Answer 18

They are more likely to cause a blockage, hinder the passage of instruments and slow down the passage of caustic substances leading to more damage.

Question 19

Describe the venous drainage of the oesophagus

Answer 19

upper and middle 3rd - azygos/hemiazygos/accessory hemiazygos. While lower 3rd goes to left gastric vein (portal system)

Question 20

What is the anstamoses between middle and lower thirds of oesophagus?

Answer 20

Portocaval anastamosis

Question 21

Describe the nerve supply of the oesophagus

Answer 21

Left vagus nerve (turns into anterior vagus trunk), right vagus nerve (turns into posterior vagus trunk)

Question 22

What nerve fibres form the oesophageal plexus?

Answer 22

The anterior vagus trunk and the posterior vagus trunk.

Question 23

Name the mediastinal lymph nodes

Answer 23

Superior and inferior tracheobronchial nodes (receives lymph from lungs - metastasis) and the anterior mediastinal lymph nodes (around brachiocephalic veins) and posterior mediastinal lymph nodes (behind heart)

Question 24

Describe the lymphatic drainage of the mediastinal lymph nodes

Answer 24

Posterior mediastinal lymph nodes drain to the paratracheal then to the bronchomediastinal lymph trunk. The anterior mediastinal lymph drains straight to the bronchomedisatinal lymph trunk

Question 25

Describe the lymphatic drainage of the left upper body.

Answer 25

The left jugular lymph trunk (LT), the left subclavian LT and the left bronchomediastinal trunk all drain to the thoracic druct which drains into the left brachiocephalic vein at pirogoffs angle

Question 26

Describe the lymphatic drainage of the right upper body

Answer 26

The right jugular LT, right subclavian LT and the right bronchomediastinal trunk all drain into the right lymphatic duct which drains into the right brachiocephalic vein.

Question 27

Describe the function of the thoracic duct

Answer 27

Carries lymph from all the body except thorax, and UL, neck and head from right side, starting from the cisterna chyli. The pulsation of the aorta promotes lymph flow (along with valves)

Question 28

What is the clinical significance of the thoracic duct

Answer 28

Lymphatic fluid can leak from the thoracic duct resulting in a chylothorax which is where lymphatic fluid enters the pleural cavity

Question 29

where will you find the thoracic duct?

Answer 29

• lies between the aorta and azygos vein in the posterior mediastinum
• at T4/5 crosses behind the oesophagus to ascend on its left side
• arches over the apex of the left lung and pleura
• opens into the left brachiocephalic vein at the junction of the left internal jugular and the left subclavian (Pirogoff’s angle)

Question 30

what side will the aorta be on in relation to the oesophagus in the thorax?

Answer 30

the aorta will be on the left in the superior mediastinum

Question 31

describe the 3 different parts of the oesophagus?

Answer 31

upper 1/3= striated muscle that is voluntary for swallowing
middle 1/3= mixed striated + smooth (mixed voluntary)
lower 1/3= smooth muscle (involuntary)

striated squamous epithelium

Question 32

at what level does the oesophagus pierce the miadstinum?

Answer 32

t10

Question 33

WHAT are the 4 constrictions of the eosophogus?

Answer 33

• upper oesophageal sphincter
• arch of aorta
• left main bronchus
• diaphragm

Question 34

what are constrictions?

Answer 34

• they are more likely to cause blockage
• hinder passage of instruments
• slow down passage of caustic substances (more damage)

Question 35

describe the venous drainage of the oesophagus?

Answer 35

• veins of the upper and middle thirds drain to azygos, hemiazygos and accessory hemiazygos
• lower third drains to the left gastric vein
• there are anastomoses between the veins of the middle and lower thirds called porto-systemic or portocaval anastomoses.