Mediastinum Flashcards
1
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Divisions and Boundaries
A
- The mediastinum is comprised of those structures that lie in the thoracic cavity, outside of the pleural cavities. It is divided into subdivisions called superior and inferior mediastinum.
- The inferior is further subdivided into three compartments, namely the anterior, middle and posterior mediastinum.
- We have already discussed the pericardial cavity and the heart, which make up the middle mediastinum.
- The anterior mediastinum is in front of the pericardial sac and contains only the thymus gland (or its remnant), the internal thoracic artery and the parasternal lymph nodes.
- The posterior mediastinum, behind the heart, contains a number of structures that are continuations of structures found in the superior mediastinum.
- The superior and inferior mediastinum are divided by drawing a plane from the sternal angle (manubriosternal joint) to the inferior portion of T4 vertebral body. Everything up to the superior thoracic inlet above this imaginary plane is in the superior mediastinum.
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14
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Superior Mediastinum
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- thymus gland
- internal thoracic arteries
- subclavian and internal jugular –> right and left brachiocephalic veins –> superior vena cava
- arch of the aorta
- brachiocephalic (inominate) –> right coomon carotid and right subclavian arteries
- left common carotid
- left subclavian
- ascending aorta
- descending aorta
- phrenic nerve
- pericardiacophrenic nerve
- right and left vagus nerves
-left recurrent laryngeal nerve (trapped by the ductus/ligamentum aretriosum)
- trachea
- esophagus
15
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Anterior Mediastinum
A
As we have mentioned, this is the area anterior to the pericardial cavity and contains only remnants of the thymus gland, the internal thoracic artery and parasternal lymph nodes.
