Superior and Posterior Mediastinum Flashcards
What is the mediastinum?
The space between the right and left pleural cavities in the thorax
What is the superior mediastinum?
The mediastinum above T4/5
What is the inferior mediastinum?
The mediastinum below T4/5
What is the anterior mediastinum?
The space in the inferior mediastinum anterior to the heart
What is the middle mediastinum?
The heart
What is the posterior mediastinum?
The space in the inferior mediastinum posterior to the heart
What is in the superior mediastinum from superficial to deep?
- thymus
- great veins
- aortic arch (with vagus and phrenic nerves)
- trachea
- oesophagus
- thoracic duct
- left recurrent laryngeal nerve
Where do the internal jugular veins and subclavian veins unite to form the brachiocephalic veins?
Behind the medial ends of the clavicle
Where do the brachiocephalic veins unite to form the SVC?
Behind the first right costal cartilage
Where does the SVC enter the right atrium?
Behind the 3rd right costal cartilage
Where does the SVC receive the azygous vein?
Behind the 2nd right costal cartilage
What are the branches of the arch of the aorta?
left and right coronary arteries, brachiocephalic trunk, left common carotid, left subclavian
What is the ligamentum arteriosum?
A fibrous band connective the underside of the arch of the aorta to the pulmonary trunk - remnant of the ductus arteriosum
What may be the result of a 4th branch of a right subclavian artery?
Compresses the oesophagus and patient presents with difficulty swallowing
What are the roots of the phrenic nerve?
C3,4,5 ventral rami
What is the path of the phrenic nerve?
Descends on scalenus anterior, travels between the subclavian artery and vein, passes anterior to the lung root, pierces the diaphragm
Where does the right phrenic nerve pierce the diaphragm?
With the IVC
Where does the left phrenic nerve pierce the diaphragm?
Alone
What are the most later structures in the mediastinum?
The phrenic nerve
What is the path of the vagus nerve?
Runs in the carotid sheath between the jugular vein and carotid artery, travels alongside the trachea, passes posterior to the lung root, forms the oesophageal plexus on the anterior surface of the oesophagus, pierces the diaphragm with the oesophagus
What is the path of the left recurrent laryngeal nerve?
Branches off the left vagus nerve as it god spast the arch of the aorta, hooks around the ligamentum arteriosum, travels back up in the groove between the trachea and oesophagus
What is the path of the right recurrent laryngeal nerve?
Branches off the right vagus nerve at the subclavian artery
Where does the trachea divide into the R and L main bronchus?
At T4/5
Where does the oesophagus pierce the diaphragm
At T10 to the left of the midline
Where does the thoracic aorta pierce the diaphragm?
At T12 between the crura
What are the structures of the posterior mediastinum?
descending thoracic aorta, oesophagus, vagus plexus, thoracic duct, azygous vein, sympathetic trunks
What are the branches of the descending thoracic aorta?
intercostal arteries, bronchial arteries, oesophageal branches, pericardial branches
What is the path of the azygous vein?
Ascends on RHS of vertebral column, arches over right lung root, enters SVC at the level of the 2nd right costal cartilage
What veins does the azygous vein receive?
The bronchial, pericardial, intercostal and oesophageal veins
What is the path of the thoracic duct?
Begins at the cistern chili, ascends at the back of the oesophagus, empties into the venous system at the junction of the left internal jugular vein and left subclavian vein
