Posterior Mediastinum Flashcards
Boundaries
Posterior: vertebral column
Anterior: pericardial sac
Superior: level of T4/sternal angle
Inferior: diaphragm (T12)
Lateral : lungs
Contents
Esophagus (posterior to pericardial sac)
Vagus nerves
Descending thoracic aortic artery
Thoracic duct (originates below diaphragm, goes up midline posterior. Shifts to left side at sternal angle)
Azygous venous system
Sympathetic chains
Esophagus surroundings
Thoracic duct and right intercostal vessels posteriorly
Left atrium anteriorly
Azygous vein can go posterior to esophagus as well.
Blood supply to esophagus
Inferior thyroid aa
Esophageal branches of aorta
Superior/inferior phrenic aa
Left gastric artery
Esophagus venous drainage
Inferior thyroid veins, azygos system on right
accessory (on top) / hemiazygos (on bottom) system on left
left gastric vein
Esophagus nerve relationships
Left vagus nerve runs anterior to esophagus
Right vagus nerve runs posterior to esophagus
Becomes Anterior / posterior vagal trunk below esophageal plexus.
Esophagus artery relationships
Thoracic aorta : left side of esophagus, but before it passes diaphragm, it goes posterior.
Esophagus lymph relationships
Thoracic duct starts posterior to esophagus (on bottom near diaphragm), shifts to left side, looping upwards to junction between subclavian vein and internal jugular vein.
Always between azygous vein and aorta
Azygous system
Right superior intercostal vein drain to arch of azygous, then drains to superior vena cava
Left superior intercostal vein passes between phrenic and vagus nerves and drains to left brachiocephalic vein (thus going to superior vena cava).
Sympathetic chain, splanctic nerves
rami communicantes
Splanctic nerves:
Greater: T5-9
Lesser: T10-11
Least: T12
Rami Communicantes: White: preganglionic sympathetic fibers
Gray: postganglionic sympathetic fibers
