Mediastinum Flashcards
Mediastinum Definition
space btw the two pleural sacs
contains all structures of thorax except for lungs and pleura
Superior Border
Thoracic Inlet
Inferior Border
Diaphragm
Anterior Border
Sternum and Costal Cartilages
Posterior Border
Thoracic Vertebrae
Division
Superior - all above sternal angle
Inferior - all below sternal angle
Inferior is divided into…
Anterior
Middle
Posterior
Superior Division Borders
Superior to sternal angle
Level of T4-T5
Structures in Superior Division
Thymus Brachiocephalic Veins SVC Aortic arch and branches Vagus Left recurrent laryngeal nerve Phrenic Trachea Thoracic Duct Esophagus Sympathetic Chain
Thymus
Superior mediastinum
Infancy and chilhood is posterior to manubrium
Adulthood it is mainly adipose tissue, only 10% is functioning
Brachiocephalic Veins
Superior Mediastinum
Form from union of internal jugular veins with subclavian
Left is twice as long as right
Branches from Aortic Arch
superior mediastinum
Brachiocephalic artery
Left CC
Left Subclavian
Inferior mediastinum Border
Inferior to sternal angle
T4-T5 through T12 vertebrae
Anterior Mediastinum Borders
Anteriorly = sternum and transversus thoracis Posteriorly = pericardium
Anterior Mediastinum Structures
Remains of thymus Loose CT Fat Lymph nodes Vessels Branches of internal thoracic artery Sternopericardial ligament
Middle Mediastinal Borders
Anteriorly - body of sternum, 2nd-6th costal cartilages
Posteriorly - 5th-8th thoracic vertebrae
Middle Mediastinal Structures
Heart Pericardium Phrenic Primary bronchi Origins of great vessels Nerves Lymphatics
What are the great vessels in middle mediastinum
Superior and Inferior Vena Cava
Ascending Aorta
Pulmonary Arteries and Veins
Lymphatics - Middle Mediastinum
Subepicardial lymph nodes
Lymph vessels - join to form single vessel
Drain into inferior tracheobronchial lymph nodes
Posterior Mediastinum Borders
Anteriorly - pericardium and diaphragm
Posteriorly - T5 to T12 vertebrae
Posterior Mediastinum Structures
Thoracic Aorta Thoracic Duct Azygos System Esophagus Nerves Lymphatics
Thoracic Aorta Branches - Posterior
Bronchial - 1 R, 2L
Esophageal - usually 2 branches
Mediastinal - to lymph nodes and other tissues
Pericardial - to pericardium
Posterior intercostals - 3rd - 11th spaces
Subcostal - under 12 rib
Superior phrenic - last branch, superior surface of diaphragm
Thoracic Duct - Posterior
Cisterna chyli - expanded end of duct at 12th vertebrae
Passes through aortic hiatus
Duck btw two gooses (esophagus and azygos)
Ascends on right side, crosses over btw T4-T6
Empties into union of left internal jugular vein and left subclavian vein
Azygos system - Posterior
Connects inferior cava to superior vena cava
