The inferior Mediastinum

Question 1

what re the divisions of the inferior mediastinum

Answer 1

anterior, middle and posterior parts.

Question 2

what is in the anterior mediastinum

Answer 2

thymus

Question 3

what is the thymus

Answer 3

e thymus is a lymphoid organ located in the lower part of the neck, posterior to the manubrium sterni and it descends into the anterior mediastinum

Question 4

what happens to the thymus after puberty

Answer 4

• undergoes gradual shrinking and is replaced by fat

- n earlier life it has a rich blood supply from the internal thoracic and inferior thyroid vessels

Question 5

what does the middle mediastinum contain

Answer 5

• heart
• pericardial sac,
• the ascending aorta,
• pulmonary trunk,
• superior vena cava,
• arch of azygos vein
• the main bronchi.

Question 6

where is the pericardium

Answer 6

t5-t8

Question 7

what is either side of the pericardial sac

Answer 7

phrenic nerves

Question 8

what is the pericardial sac fused with

Answer 8

• central tendon of the diaphrgam

- tunica adventitia of the great vessels

Question 9

what is the nerve supply of the fibrous and partial pericardium

Answer 9

C3-C5

Question 10

what are the 3 surfaces of the heart

Answer 10

1. ) The anterior (or sternocostal) surface is formed mainly by the right ventricle although all four chambers are represented on this surface.
2. ) The inferior (or diaphragmatic) surface is formed mainly by the left ventricle with a contribution from the right ventricle. It is closely related to the central tendon of the diaphragm.
3. ) The left (or pulmonary) surface is formed mainly by the left ventricle. This is the surface which occupies the cardiac notch on the left lung.

Question 11

where is the posterior mediastinum located

Answer 11

The posterior mediastinum is located between T5-12, posterior to the pericardium and the diaphragm, and between the parietal pleura of the 2 lungs

Question 12

what is in the posterior mediastinum

Answer 12

oesophagus and oesophageal plexus
thoracic (descending) aorta
thoracic duct
azygos and hemi-azygos veins
sympathetic trunks and splanchnic nerves.

Question 13

where does the thoracic aorta begin

Answer 13

• begins left side of the body at t4

- descends on left side of T5-T12, entering abdomen at T12 through the aortic hiatus

Question 14

what are the branches of the thoracic aorta

Answer 14

bronchial, pericardial, posterior intercostal arteries and then superior phrenic arteries

Question 15

where do the azygous and semi azygos veins originate

Answer 15

abdomen

Question 16

where do the azygous and hemiazgous vein drain blood from

Answer 16

posterior intercostal spaces, the posterior abdominal wall, the pericardium, the diaphragm and the bronchii

Question 17

where does the semi azygous vein cross

Answer 17

cross anterior to the bodies of T7 and T8

Question 18

where does the azygous vein enter

Answer 18

The azygos vein drains up through the right side of the thorax and enters the posterior portion of the superior vena cava just before it enters the right atrium