Chapter 6 - Mediastinum

Question 1

Boundaries of superior mediastinum

Answer 1

A: Manubrium
P: T1-T4
S: Thoracic inlet
I: Imaginary plane through sternal angle and lower border of T4
Side: Mediatinal pleura

Question 2

Contents of superior mediastinum

Answer 2

1. Trachea
2. Oesophagus
3. Sternothyroid, sternohyoid, longus colli
4. Arch of aorta
   Brachiocephalic A
   Left common carotid A
   Left subclavian A
5. R, L brachiocephalic V
   Superior vena cava
   Left superior intercostal V
6. Vagus N
   Phrenic N
   Cardiac N
   Left recurrent laryngeal N
7. Thymus
8. Thoracic duct
9. Lymph nodes

Question 3

Boundaries of anterior mdiastinum

Answer 3

A: Sternum
P: Pericardium
S: Imaginary plane through sternal angle and lower border of T4
I: Diaphragm
Sides: Mediastinal pleura

Question 4

Contents of anterior mediastinum

Answer 4

1. Sternopericardial ligaments
2. Lymph nodes
3. Mediastinal branches of internal thoracic A
4. Thymus
5. Areolar tissue

Question 5

Boundaries of middle mediastinum

Answer 5

A: Sternopericardial ligaments
P: Oesophagus, Descending aorta, Azygos V
Sides: Mediastinal pleura

Question 6

Contents of middle mediastinum

Answer 6

1. Heart
2. Ascending aorta
   Pulmonary trunk
   2 pulmonary A
3. Superior vena cava
   Azygos V
   Left pulmonary V
4. Phrenic N
   Deep cardiac plexus
5. Tracheobronchal lymph nodes
6. Bifurcation of trachea

Question 7

Boundaries of posterior mediastinum

Answer 7

A: Pericardium bifurcation of trachea, pulmonary vessels
P: T5-T12
Sides: Mediastinal pleura

Question 8

Contents of posterior mediastinum

Answer 8

1. Oesophagus
2. Descending thoracic aorta
3. Azygos, hemiazygos, accessory hemiazygos V
4. Vagus, splanchnic N
5. Thoracic duct

Question 9

Mediastinal syndrome

Answer 9

• Caused by compression of mediastinal structures by tumor
• Ex: Bronchiogenic carcinoma, Hodgkin’s disease, aneurysm.

1. Obstruction of superior vena cava causes enlarged veins
2. Pressure over trachea: dyspnoea
3. P/O oesophagus: dysphagia
4. P/O left recurrent laryngeal N: hoarse voice
5. P/O phrenic N: paralysis of diaphragm
6. P/O intercostal N: intercostal neuralgia
7. P/O vertebral column: erosion of vertebral bodies