Superior and Posterior Mediastinum Flashcards
What are the borders of the Superior Mediastinum?
- Superior–> Thoracic Inlet
- Inferior–> Level T4
- Anterior–> Manubrium of Sternum
- Posterior–> Vertebral bodies T1-T4
- Lateral–> Pleura of Lungs
What are the contents of the Superior Mediastinum?
- Great Arteries and Vein
- Oesophagus
- Trachea
- Vagus and Phrenic Nerves
- Thoracic Duct
What are the branches of the Arch of Aorta?
- Descending Aorta
- Brachiocephalic–> Branches into the right subclavian and right common carotid
- Left Common Caortid
- Left Subclavian
Where does the Superior Vena Cava bifurcate into the right and left brachiocephalic veins?
At the level of Costal Cartilage 1
Where does the Azygous vein join up with the Superior Vena Cava?
At level T4, level of Costal Cartilage 2
Where doe the Superior Vena Cava enter the right atrium of the heart?
At the level of Costal Cartilage 3
Where does the right vagus nerve run?
Runs parallel to the trachea, passing anteriorly to the origin of (hooks over) the right subclavian artery and gives of the right recurrent laryngeal nerve which hooks under the right subclavian artery to supply the muscles of the larynx–> can be affected by conditions at the apex of the lung e.g. Pancoasts Tumour
Where does the left vagus nerve run?
Enters the superior mediastinum between the left common carotid and left subclavian arteries, passes over the aortic arch and gives off the left recurrent laryngeal nerve which hook under the the arch of aorta to supply the muscles of the larynx–> can be affected by enlarged lymph nodes
Where does the Right Phrenic Nerve run?
On the right wall of the Superior Vena Cava and directly to the right side of the fibrous pericardium
Where does the Left Phrenic Nerve run?
Passes over the left side of the arch of aorta and the left pulmonary artery, then descends on the pericardium over the left ventricle to the diaphragm near the cardiac apex
What are the borders of the posterior mediastinum?
- Lateral–> Mediastinal Pleura
- Anterior–> Pericardium
- Posterior–> T5-T12 vertebrae
- Superior–> Level T4
- Inferior–> Diaphragm
What are the contents of the posterior mediastinum?
- Great Arteries and Vein
- Oesophagus
- Trachea
- Vagus and Phrenic Nerves
- Thoracic Duct
- Sympathetic Chain
What is the arterial supply to the posterior mediastinum?
- Posterior Intercostal arteries–> 1st and 2nd arise from the subclavian, 3rd onwards from the descending aorta
- Oesophagal Arteries to Oesophagus
- Superior Phrenic Arteries to Superior aspect of diaphragm
What is the venous drainage of the posterior mediastinum?
The Azygous system
Describe the Azygous system
Right Side: Azygous Vein
Left Side: Accessory Hemiazygous (T4-T8) and Hemiazygous (T9-T12)
Describe the lymphatic drainage of the posterior mediastinum
Via the Thoracic Duct, starting from the Cisterna Chyli at L2–> receives drainage from intercostal nodes, parasternal nodes and diaphragmatic nodes. Right side drains into the jugular trunk and right subclavian, left side drains directly into the left subclavian
Where is the Sternal Origin of the Diaphragm?
Level T8
What passes through the Diaphragm at Level T8?
Inferior Vena Cava and Right Phrenic Nerve
Where is the Vertebral Origin of the Diaphragm?
Level T10
What passes through the diaphragm at level T10?
Vagus Nerves and Oesophagus
Where is the Costal Origin of the diaphragm?
Level T12
What passes through the diaphragm at Level T12?
Aorta, Thoracic Duct and Azygous Vein
What is the nervous supply of the Diaphragm?
Phrenic Nerves from C3,4,5
What is the Arterial Supply of the Diaphragm?
- Inferior Phrenic Arteries
- Superior Phrenic Arteries
- Musculophrenic Arteries
- Pericardiophrenic Arteries
