Mediastinum

Question 1

What are the contents of the posterior mediastinum?

Answer 1

“4 geese, 2 ducks, and 1 aorta”

1. azygous vein
2. hemiazygous vein (possibly accessory hemiazygous vein)
3. esophogus
4. vagus
5. thoracic duct
6. sympathetic duct
7. aorta

Question 2

What are the contents of the superior mediastinum?

Answer 2

great vessels (aorta, vena cava), trachea, esophogus, thymus

Question 3

What are the different paths of the recurrent laryngeal nerves?

Answer 3

cranial nerve X –> right vagus nerve –> under the subclavian artery –> right recurrent laryngeal nerve

cranial nerve X –> left vagus nerve –> under the aortic arch –> left recurrent laryngeal nerve

Question 4

Describe the injuries to the L/R recurrent laryngeal nerves and the causes of the of them.

Answer 4

Bilateral injury: loss of voice, difficulty breathing
Unilateral injury: hoarseness of voice, difficulty breathing

Causes: thyroid/parathyroid injury during surgery, lung cancer induced compression of the nerve (most common on the left side)

Question 5

What is the significance of the thoracic duct and where does it drain into ?

Answer 5

The thoracic duct is the largest lymphatic channel in the body. It originates in the abdomen, travels up through the aortic hiatus, and then up to the vein. It empties into the opening at the level of the LEFT BRACHIOCEPHALIC VEIN

Question 6

What is the phrenic nerve, where is it located and what does it innervate?

Answer 6

The phrenic nerve originates on C3,C4,C5 (keeps you alive). It runs along the heart to provide sensory innervation to the fibrous pericardium (fibrous and parietal) and then provides motor innervation to the diaphragm.