Exam 3: Mediastinum Part 1

  1. What is the mediastinum?
    3-D space between pleural cavities that extends vertically from thoracic inlet and to thoracic outlet
  2. What are the divisions of the mediastinum?
    • superior mediastinum
    • inferior mediastinum 
  3. What separates the superior mediastinum from the inferior mediastinum?
    imaginary plane that passes through sternal angle and interverterbral disc between T4-5 vertebrae
  4. Which vessel is just below the superior mediastinum?
    pulmonary trunk and arteries
  5. Where is the inferior mediastinum?
    lies below the imaginary plane separating the two divisions
  6. What are the subdivisions of the inferior mediastinum?
    • anterior
    • middle
    • posterior
  7. What makes up the middle (central) component of the inferior mediastinum?
    heart and pericardium
  8. What is contained in the superior mediastinum?
    • all structures entering and exiting thoracic inlet
    • thymus gland
    • great vessels of heart
    • ligamentum arteriosum
    • 3 branches of aortic arch
    • phrenic nerves
    • vagal nerves
    • left recurrent laryngeal nerve
    • trachea
    • esophagus
    • cardiac plexuses           
  9. Where is the thymus gland found?
    • superior mediastinum
    • anterior mediastinum
  10. Where is the anterior mediastinum?
    located posterior to sternum, just in front of pericardium
  11. What is found in the anterior mediastinum?
    thymus gland
  12. Which mediastinum are the heart and pericardial sac found?
    middle mediastinum
  13. Where is the middle mediastinum located?
    between anterior and posterior mediastinum
  14. Where is the posterior mediastinum located?
    • between middle mediastinum (pericardium) and anterior longitudinal ligament
    • stretches from T5-12 
  15. What does the anterior longitudinal ligament cover?
    anterior surface of vertebral column
  16. What is contained in the posterior mediastinum?
    structures oriented either vertically or horizontally
  17. What vertically oriented structures are found in the posterior mediastinum?
    • descending thoracic aorta
    • thoracic duct
    • esophagus
    • vagus nerves
    • azygos system of veins
    • greater splanchnic nerve     
  18. What horizontally oriented structures are found in the posterior mediastinum?
    intercostal arteries, veins, and nerves 
  19. What is the esophagus? What does it connect?
    muscular tube connecting pharynx w/ stomach
  20. Where does the esophagus begin?
    • in neck
    • level of larynx/C6 vertebra 
  21. What does the esophagus descend through?
  22. What does the esophagus lie next to? 
  23. After the esophagus descends through the thorax what does it enter?
    abdominal cavity
  24. What does the esophagus pass through before it enters the abdominal cavity?
    esophageal hiatus in respiratory diaphragm
  25. Is the esophagus normally collapsed or held open?
  26. Approximately how wide is the esophagus?
    1" wide
  27. About how long is the esophagus?
    12" long
  28. The esophagus extends vertically from which vertebrae levels?
  29. Where are the locations of the constrictions of the esophagus?
    • at commencement (origin)
    • where passes posterior to aortic arch
    • where passes posterior to left main bronchus
    • where passes through esophageal hiatus
  30. Why are the constrictions of the esophagus important?
    • constrictions can adhese and block the pathway for food
    • doctors must know location when doing a scope 
  31. Is the esophagus anterior or posterior to the anterior longitudinal ligament?
  32. While in the neck and superior mediatinum, the esophagus is anteiror or posterior to the trachea?
  33. While in inferior mediastinum, the esophagus is anterior or posterior to left atrim?
  34. What innervates the esophagus?
    vagal nerves from nerve network
  35. The vagal nerves come from which nerve network?
    esophageal plexus
  36. Where is the esophageal plexus?
    on external surface of esophagus
  37. Do the vagal nerves provide sensory or motor fibers to the esophagus?
  38. Where does the arterial supply of the esophagus begin?
    in cervical region
  39. Where does the arterial supply of the esophagus extend?
    to abdominal region
  40. What provides arterial supply to the esophagus?
    • inferior thyroid arteries
    • bronchial arteries
    • aortic esophageal arteries (2 or 3)
    • left gastric artery
    • inferior phrenic arteries
  41. What do the esophageal veins correspond to?
    the arteries which supply it
  42. Many of the esophageal veins are tributaries to what?
    azygos system of veins
  43. Why is venous drainage of esophagus clinically important?
    possibility of esophageal varices, observed in patients w/ cirrhosis of the liver
  44. The left gastric vein provides dirct connection between what?
    esophageal venous plexus and hepatic portal system
  45. Where does the hepatic portal system receive venous blood from?
    gastrointestinal tract
  46. What can the venous blood from the gastrointestinal tract bypass and return to the right atrium?
    cirrhotic liver
  47. How does venous blood bypass a cirrhotic liver and return to the right atrium?
    via esophageal venous plexus
  48. What happens if esophageal venous plexus becomes engorged with blood?
    • causes many vessels to dilate and become subject to rupture
    • esophageal varicise (varicose veins in esophagus) 
  49. Where does the esophageal lymphatic plexus drain?
    posterior intercostal and mediastinal nodes
  50. Where do the posterior intercostal and mediastinal nodes drain to?
    thoracic duct and/or bronchomediastinal trunks
  51. What is the descending thoracic aorta continuous with?
    aortic arch
  52. What vertebrae levels does the descending thoracic aorta run along?
    extends from T4-12
  53. What is at the level of T4-12 vertebrae?
    aortic hiatus in diaphragm
  54. Where does the descending thoracic aorta deviate?
    from left toward midline
  55. What are the branches of the descending thoracic aorta in the thorax (posterior mediastinum)?
    • bronchial
    • esophageal
    • pericardial
    • mediastinal arteries to lymph nodes
    • posterior intercostal 
    • subcostal arteries    
  56. How many pairs of posterior intercostal areteries are there from the descending thoracic aorta?
    8 pairs
  57. What do the 8 pairs of posteiror intercostal arteries supply?
    intercostal spaces 3-11
  58. How many subcostal arteries are there?
    one pair
  59. Where does the azygos system of veins collect blood from?
    • posterior intercostal spaces
    • esophagus
    • respiratory diaphragm
    • pericardium
    • bronchi  
  60. Are the azygos system of veins fairly consistent from one body to the next?
    no, considerable individual variation
  61. Where does the azygos system of veins commence (begin)?
    at inferior vena cava
  62. Where does the azygos system of veins ascend?
    along vertebral bodies
  63. Where does the azygos system of veins terminate?
    in superior vena cava (arches over right main bronchus)
  64. Where are the hemiazygos veins?
    on left side of aorta
  65. What are the hemiazygos veins tributaries to?
    azygos vein
  66. What are the tributaties to the azygos system of veins?
    • posteiror intercostal
    • esophageal
    • phrenic
    • bronchial
    • pericardial
    • mediastinal
  67. Does the right recurrent laryngeal nerve enter the thorax?
    no, it is only in the nck
  68. Which nerve is next to the ligamentum arteriosum?
    left recurrent laryngeal N
  69. What was the ligamentum arteriosum in the embryo?
    ductus arteriosus (vessel in embryo that closes off to form ligament)
  70. What is the thymus gland important in?
    in immune system
  71. When is the thymus gland large?
    in infants
  72. What is the size and shape of the thymus in newborns?
  73. What do doctors called large thymus glands in newborns?
    Thymic "sail"
  74. Within the first years of life, T-cells in the thymus leave the gland to go where?
    to other lymphatics throughout body to set up clones to produce T-cells
  75. After migration of the T-cells, what happens to the thymus gland?
    gets smaller (happens by age 2 or 3)
  76. After migration, what is left of the thymus gland? 
    • fatty connective tissue
    • no functional thymic tissues 
  77. Which arteries supply thymus gland?
    internal thoracic arteries, not aorta
  78. Where is the boundary line between the superior and inferior mediastinum?
    line between aorta and pulmonary trunk
  79. Does the trachea go into inferior mediastinum?
    no, because it splits before
Card Set
Exam 3: Mediastinum Part 1
review of 7/12 lecture on Mediastinum for exam 3