Posterior mediastinum

Question 1

Boundaries

Answer 1

Anterior: Posterior pericardium 
Posterior: Vertebrae T5-12
Lateral: Mediastinal pleura 
Superior: transverse thoracic plane 
Inferior diaphragm

Question 2

Contains

Answer 2

Oesophagus 
Thoracic aorta 
Azygous system of veins 
Thoracic duct 
Vagus nerve 
Sympathetic trunk 
Splanchnic nerves

Question 3

Structures that transcend into the superior mediastinum

Answer 3

Oesophagus
Thoracic duct 
Vagus Nerve
Phrenic nerve
Aorta

Question 4

Thoracic aorta

Answer 4

Continuous with arch of aorta
Descends on the left side of vertebrae T5-12
Oesophagus positioned to its right
Terminates at vertebral level T12 where it enters the abdomen through the aortic hiatus in the diaphragm
Thoracic duct and azygous veins ascend on its right hand side and also pass through diaphragm at the aortic hiatus

Question 5

Thoracic aorta branches

Answer 5

Bronchial 
Posterior intercostal (12)
Subcostal (12th bundle)
Pericardial 
Oesophageal 
Superior phrenic (supplies the superior aspect of the diaphragm)

Question 6

Azygous vein location

Answer 6

Usually located ascending to the right side of the thoracic vertebra

Question 7

Azygous vein function

Answer 7

Drains deoxygenated blood from the posterior thoraco-abdominal walls and viscera

Question 8

What drains into the azygous vein

Answer 8

Posterior intercostal veins, bronchial veins, vertebral venous plexus drain into it

Question 9

Azygous vein

Answer 9

Arches over root of right lung to join SVC
Usually receives blood from the hemiazygous veins which drain the left side
Forms a collateral pathway between the SVC and IVC

Question 10

Hemi-azygous veins

Answer 10

Arises on the left side by junction of subcostal (T12 level) and ascending lumbar veins
Ascends on the left side posterior aorta draining left posterior intercostal veins levels T9-11
Crosses towards the right and joins the azygous

Question 11

Accessory hemi-azygous

Answer 11

Accessory hemi-azygous drains into levels T4-T8 on left side
Crosses T7/8 to join azygous and sometimes joins hemi-azygous

Question 12

Thoracic duct

Answer 12

Largest lymph channel
Conveys all lymph from body except the head, neck, upper limb and thorax on right side
Originates in the cisterna chyli in abdomen
Ascends through the aortic hiatus passing anterior to thoracic vertebrae
Ascends into superior mediastinum and drains into venous system at the left venous angle