Thorax: Posterior mediastinum and thoracic exit

Question 1

Major contents of the posterior mediastinum

Answer 1

Nerve plexus
Esophagus
Thoracic aorta and branches
Azygos system of veins
Thoracic duct
Sympathetic trunk and thoraco-splanchnic nerves.

Question 2

At which vertebral levels does the oesophagus starts and ends?

Answer 2

Starts at C6 and ends at T11.

Question 3

How does the oesophagus pass through the diaphragm?

Answer 3

Via the oesophageal hiatus at T10.

Question 4

Four locations whereby the oesophagus is compressed?

Answer 4

• Junction btwn the pharynx and oesophagus.
• When it crosses the aorta.
• By the left main bronchus.
• At the oesophageal hiatus of diaphragm.

Question 5

At which vertebral levels does the descending thoracic aorta starts and ends?

Answer 5

Starts at T4/T5 and ends at T12.

Question 6

How does the thoracic aorta pass through the diaphragm?

Answer 6

Aortic hiatus of diaphragm.

Question 7

Branches that are given off by the descending thoracic aorta? (7)

Answer 7

-Bronchial branches
-Mediastinal branches
-Oesophageal branches
-Pericardial branches
- Posterior intercostal arteries
-Subcostal artery
-Superior phrenic arteries

Question 8

The azygos system of veins is made up of:

Answer 8

-Azygos vein (right)
-Accessory hemiazygos vein (left, superiorly)
-Hemiazygos vein (left, inferiorly)

Question 9

How does the azygos vein enter the thorax?

Answer 9

Via the aortic hiatus of diaphragm or posterior to the right crus of diaphragm.

Question 10

What are the tributaries of the azygos vein? (9)

Answer 10

-Right superior intercostal vein
-5th-11th posterior intercostal veins
-Hemiazygos vein
-Accessory hemiazygos vein
-Mediastinal vein
-Oesophageal vein
-Pericardial vein
-Right bronchial vein
-Right ascending lumbar and subcostal vein

Question 11

How does the hemiazygos vein enter the thorax? (2)

Answer 11

It enters posterior to the left crus f the diaphragm, it may also enter via the aortic hiatus.

Question 12

At which vertebral level does the hemiazygos vein cross the vertebral column to join the azygos vein?

Answer 12

T8

Question 13

Tributaries of the hemiazygos vein? (4)

Answer 13

-9th-11th posterior intercostal veins
-Oesophageal vein
-Mediastinal vein
-Left bronchial vein (sometimes)

Question 14

Tributaries of the accessory hemiazygos vein(2)

Answer 14

-4th/5th-8th posterior intercostal veins
-Left bronchial vein (sometimes)

Question 15

Principal lymphatic channel that drains lymph from most of the body?

Answer 15

Lymphatic duct

Question 16

At which vertebral level does the cysterna chyli extends?

Answer 16

L2

Question 17

How does the thoracic duct enter the thorax?

Answer 17

Via the aortic hiatus

Question 18

Which lymphatic vessels drain into the thoracic duct?

Answer 18

-The left jugular trunk and left subclavian trunk.

Question 19

Where does the thoracic duct empty its contents?

Answer 19

At the junction btwn the left internal jugular and subclavian veins.

Question 20

Lymphatic nodes responsible for the drainage of subcutaneous tissue?

Answer 20

Axillary lymph nodes

Question 21

Five types of axillary lymph nodes

Answer 21

-Apical
-Central
-Anterior
-Posterior
-Lateral

Question 22

Where do the axillary lymph nodes drain into?

Answer 22

The anterior, lateral, and posterior drain into the central.
-The central drains into the apical.
-Apical into the subclavian trunk.

Question 23

Lymph nodes resp. for drainage of deeper tissues and thoracic wall? (3)

Answer 23

-Intercostal nodes
-Parasternal nodes
-Diaphragmatic nodes

Question 24

Lymph nodes resp. for the drainage of sup. and deep lymphatic of lung?

Answer 24

Tracheobronchial nodes

Question 25

Where do the ff nodes drain into?
a. Diaphragmatic
b. Parasternal, bronchocephalic and tracheobronchial
c. intercostal

Answer 25

a. They interconnect either with parasternal or bronchocephalic.
b. Into the bronchomediastinal trunk
c Upper nodes into the bronchomediastinal trunk, lower nodes into the thoracic duct.

Question 26

How many ganglia of the sympathetic trunk do we have in the diff vertebral regions?

Answer 26

-Cervial: 3
-Thoracic: 11-12
- Lumbar: 4
-Sacral: 4-5

Question 27

Structure formed when the sympathetic trunks combine in the coccyx?

Answer 27

Ganglion impar

Question 28

What do we call the ganglion found in btwn the cervical and thoracic regions?

Answer 28

-Cervicothoracic ganglion/ stellate ganglion

Question 29

What connects the ganglia of the sympathetic trunks and the thoracic spinal nerves?

Answer 29

Grey and white rami communicantes

Question 30

How is the diaphragm attached to lumbar vertebrae?

Answer 30

Via the right and left cruca

Question 31

At which vertebral levels are the right and left cruca found?

Answer 31

Left crus- L1 & L2
Right crus- L1-L3

Question 32

Three ligaments of the diaphragm?

Answer 32

-Median, medial and lateral arcuate ligaments

Question 33

What forms the medial arcuate ligament?

Answer 33

The fascia covering the psoas major.

Question 34

What forms the lateral arcuate ligament?

Answer 34

The fascia covering the quadratus lumborum.

Question 35

Arterial supply of the diaphragm

Answer 35

*Superior surface:
-Musculophrenic artery
-Superior phrenic artery
-Pericardiacophrenic artery
-Intercostal artery
*Inferior surface
-Inferior phrenic artery

Question 36

Innervation of the diaphragm

Answer 36

Motor innervation: Phrenic nerve

Sensory innervation:
Phrenic nerve (central part)
Intercostal nerve (peripheral part)