Mediastinum

Question 1

What divides the mediastinum into superior and inferior mediastina?

Answer 1

The transverse thoracic plane, TPP

Question 2

What are the compartments of the inferior mediastinum?

Answer 2

Anterior, middle and posterior mediastina

Question 3

Where can the transverse thoracic plane of Ludwig be found?

Answer 3

Runs thought the level of the manubrio-sternal angle of Louis and T4 intervertebral disc

Question 4

What are the ABC’s of the TTP?

Answer 4

Arches: Aortic arch on the left, Azygous on the right

Bifurcations: tracheal and pulmonary trunk Bifurcations

Change in direction: esophagus and thoracic duct

Question 5

What other structures can be found at the TTP besides the ABCs?

Answer 5

Tracheobronchial lymph nodes
Cardiac and pulmonary plexuses
Ligamentum arteriosum

Question 6

Where is the superior mediastinum located?

Answer 6

Between the TTP and superior thoracic aperture

Question 7

Where is the Thymus gland located?

Answer 7

In the inferior part of the neck and anterior part of the superior mediastinum, especially in children whom it is relatively large and readily recognizable on a chest X-ray

Question 8

When does the thymus undergo involution?

Answer 8

After puberty

Question 9

What is the thymus gland for?

Answer 9

Training of T-lymphocytes as part of cell-mediated immunity (CMI)

Question 10

Where does the thymus receive its vasculature?

Answer 10

Mainly from branches of the internal thoracic artery

Question 11

Where does the thymus gland’s lymph nodes drain into?

Answer 11

Para sternal nodes

Question 12

What carcinoma is commonly seen in the thymus gland and with what disease is it commonly seen?

Answer 12

Malignant thymoma

Myasthenia gravis

Question 13

What is the relationship between thymoma and myasthenia Travis?

Answer 13

50% of cortical thymoma patients develop myesthenia graves

15% of myasthenia gravis patients develop thymoma

Question 14

What is myasthenia gravis?

Answer 14

An autoimmune neuromuscular junction disease caused in 85% of cases by acetylcholine receptor (AChR) antibodies

Question 15

What forms the brachiocephalic vein?

Answer 15

Internal jugular and subclavian veins

Question 16

How is the superior vena cava (SVC) and at what level is it found?

Answer 16

The left brachiocephalic vein crosses the midline to join the right brachiocephalic being to form the SVC at the level of the first chondrosternal joint, postero-lateral to the right margin of the sternum

Question 17

When does the SVC receive the azygous vein?

Answer 17

At the level of the second chondrosternal joint

Question 18

Where does the SVC end?

Answer 18

At the right atrium at the level of the 3rd sternochondral joint

Question 19

Where does the SVC collect blood from?

Answer 19

Upper half of the trunk, upper limbs and head/neck

Question 20

What does compression of the SVC lead to?

Answer 20

Superior mediastinal/VC syndrome

Symptoms: blu head, neck and upper limbs with engorged superficial veins

Question 21

What are the arteries of the superior mediastinum?

Answer 21

Upper part of the arch of the aorta (and branches), namely the Brachiocephalic trunk, left common carotid and left subclavian arteries

Question 22

Where does the arch of the aorta start?

Answer 22

Posterioylteral to the second sternochondrial joint at the level of the TTP)

Question 23

Where is the concavity of the arch of the aorta?

Answer 23

TTP

Question 24

What are the 3 bregular branches of the arch of the aorta

Answer 24

Brachiocephalic trunk, left common carotid artery and left subclavian artery

Question 25

What is the first branch of the aortic arch?

Answer 25

Brachiocephalic trunk which arises from the apex of the arch anterior to the trachea

Question 26

What does the brachiocephalic trunk divide into and where?

Answer 26

Behind the first venous angle ( behind the right sternoclavicular joint) into the right subclavian and right common carotid arteries

Question 27

What do the branches of the brachiocephalic trunk supply?

Answer 27

Right subclavian: the upper limb Right common carotid arteries: head and neck region

Question 28

Where does the left common carotid artery arise from?

Answer 28

The second branch of the aortic arch from its convex surface (on the left side of the brachiocephalic trunk, trachea and esophagus)

Question 29

What path does the left common carotid artery follow?

Answer 29

It runs upwards and to the left of the trachea to enter the root of the neck behind the left sternoclavicular joint

Question 30

Where does the left subclavian artery arise from?

Answer 30

The aortic arch on the descending part of the arch, just to the left of the left common carotid artery

Question 31

What is the path of the left subclavian artery and what does it supply?

Answer 31

It runs upward along the left side of the trachea and esophagus to enter the root of the neck by arching over the lun apex, to supply branches to the neck, thorax and upper limb.

Question 32

What does the left subclavian artery become and where?

Answer 32

The axillary artery at the lateral margin of the first rib

Question 33

What are the branches of the Left subclavian artery?

Answer 33

VIT C and D

Question 34

Where is the trachea located?

Answer 34

Anterior to the esophagus ad posterior to the thyroid gland in the neck

Question 35

Where does the trachea bifurcate and into what?

Answer 35

Below the carina into the left and right main stem bronchi at (T4 IVD,TTP, sternal angle)

Question 36

What is tracheomalacia?

Answer 36

A disorder in infants in which the trachea lacks structural support so that the negative airway pressures generated during inspiration causes the trachea to collapse. Results in: a strider during inspiration (high-pitched whistling sound)

Question 37

How is the esophagus different than other digestive organs?

Answer 37

It lacks serosa

Question 38

What supplies blood to the esophagus?

Answer 38

Inferior thyroid Bronchial arteries, DTA Left gastric Inferior phrenic arteries

Question 39

Where do the esophageal veins empty into?

Answer 39

Portal venous system

Question 40

What is the MC cause of portal hypertension?

Answer 40

Cirrhosis of the liver in chronic alcoholics Schistosomiasis in the tropics

Question 41

Esophageal varices are dilated veins of the esophagus commonly seen in what conditions?

Answer 41

Portal hypertension

Question 42

What are the 5 nerves of the superior mediastinum?

Answer 42

Two vagus Two phrenic left recurrent laryngeal nerve

Question 43

Where is the left recurrent laryngeal nerve given off the vagus nerve?

Answer 43

Between the last two arteries of the arch of the aorta (left carotid and left subclavian)

Question 44

What does the phrenic nerve innervate?

Answer 44

3 P's (pleura, pericardiu and peritoneum) | Thoracic part of the thoracic diaphragm

Question 45

Where does the right phrenic artery lie?

Answer 45

To the right side of the brachiocephalic vein, superior vena cava, right atrium, inferior vena cava before entering the abdomen through the inferior caval opening

Question 46

Where does the left phrenic nerve lie?

Answer 46

Between the left brachiocephalic vein and the last two branches of the aortic arch, on the left side of the left atrium and left ventricle before piercing the thoracic diaphragm near the cardiac apex

Question 47

Where is the ascending aorta located?

Answer 47

Anterior to the mediastinum

Question 48

Where does the ascending aorta come from?

Answer 48

At first behind the pulmonary trunk and to the left of superior vena cava then between the two before arching back towards the posterior mediastinum as the arch of aorta.

Question 49

The arch and ascending aorta and their neighbors are covered by the inferior part of what gland?

Answer 49

Thymus gland

Question 50

What does the posterior mediastinum contain | (Inferior)?

Answer 50

Posterior mediastinal lymph nodes Thoracic duct ``` Sympathetic trunk Azygous system of veins Descending thoracic aorta Lymphatic trunk Esophagus ```

Question 51

Where is the descending thoracic aorta located?

Answer 51

Left side of the vertebral column and thoracic duct, posterior to the esophagus, and anterior to the azygous veins. It passes behind the thoracic diaphragm at T12 (aortic hiatus) to enter the abdomen

Question 52

What are the branches of the descending aorta?

Answer 52

Bronchial (2 Lt) Esophageal Subcostal (one on each side) Tracheal Pericardial Intercostal Mediastinal Phrenic (Superior)

Question 53

What accompanies the the descending aorta through the aortic hiatus at T12?

Answer 53

Thoracic duct and azygous vein

Question 54

What is the largest lymphatic vessels in the venous system? (About 75% of drainage)

Answer 54

Thoracic duct

Question 55

What does the thoracic duct drain?

Answer 55

Both halves of the body below the thoracic diaphragm and left side of the body above the thoracic diaphragm

Question 56

What are the tributaries to the thoracic trunk in the thorax and in the abdomen?

Answer 56

Thorax: left jugular, left subclavian and left brnchomediastinal trunks Abdomen: lumbar and intestinal lymphatic trunks

Question 57

What makes up the azygous system of veins?

Answer 57

Azygous Hemiazigous Accessory hemiazygous

Question 58

Where are the azygous system veins located?

Answer 58

Right side: azygous Left side: hemiazygous and accosts hemiazygous

Question 59

How does the sympathetic chain (splanchnic) leave the thoracic cavity?

Answer 59

By passing deep to the medial accurate ligament of the thoracic diaphragm

Question 60

What do the upper 5 splanchnic nerves supply?

Answer 60

The thoracic viscera