Mediastinum Flashcards
anterior boundary of the mediastinum
sternum, costal cartilages
posterior boundary of the mediastinum
thoracic vertebral bodies
lateral boundaries of the mediastinum
mediastinal pleura
location of superior mediastinum
posterior to manubrium of the sternum, and anterior to the first 4 thoracic vertebrae
structures in the superior mediastinum from anterior to posterior
- thymus
- right and left brachiocephalic veins
- superior vena cava
- arch of the aorta and its branches (brachiocephalic trunks, common carotid, subclavian)
- trachea and esophagus
- phrenic and vagus nerves
- left recurrent laryngeal nerve
- thoracic duct
label superior mediastinum
location of thymus
most anterior compartment in superior mediastinum, directly anterior to the right and left brachiocephalic veins (that come off the superior vena cava)
characteristic of thymus
large in children, atrophy after puberty, is a thymic remnant in elderly
function of thymus
was involved in the early development of the immune system
what forms the brachiocephalic veins
formed by the union of the internal jugular and subclavian veins before the left brachiocephalic vein crosses midline to join with the right brachiocephalic vein to form superior vena cava
label aortic arch and branches
location of esophagus
posterior to trachea, but anterior to thoracic vertebrae in superior mediastinum, connects pharynx and stomach
innervation of esophagus
the vagus nerves form esophageal plexus
branches of vagal nerves
left and right vagal nerves come together to form esophageal plexus, then the fibers reform to make anterior vagal trunk and posterior vagal trunk around the esophagus
contribution of anterior and posterior vagal trunks
left vagal nerve becomes the anterior vagal trunk and the right vagal nerve becomes the posteiror vagal trunk
contribution of phrenic nerve
C3,C4,C5
location of phrenic nerve
passes anterior to lung roots between mediastinal pleura and pericardium
what does the phrenic nerve innervate
motor and sensory diaphragm, sensory innervation to mediastinal pleura, fibrous pericardium, parietal pericardium
innervation of vagus nerves
parasymphathetic innervation to thoracic and abdominal viscera, branches superiorly to the left and right recurrent laryngeal nerves
location of vagus nerves
pass posterior to lung roots
location of left recurrent laryngeal nerve
passes inferior to arch of aorta, then ascends in a groove between the trachea and esophagus
location of right recurrent laryngeal nerve
branches at the split of the brachiocephalic trunk into the right common carotid and the right subclavian artery
that is the function of the thoracic duct
is the principal channel through which lymph from most of the body is returned to the venous system
location of thoracic duct
posterior to esophagus in between aorta and azygos vein, it enters the inferior portion of the superior mediastinum to the left venous angle to empty into the junction of the left subclavian and left internal jugular veins
location of the anterior inferior mediastinum
posterior to the body of the sternum and anterior to pericardial sac
anterior mediastinum contains
portion of thymus and internal thoracic blood vessels
location of middle mediastinum
centrally located, in thoracic cavity
contents of middle mediastinum
pericardium, heart, origins of great vessels and various nerves
location of posterior mediastinum
posterior to pericardial sac, anterior to vertebral bodies of mid and lower thoracic vertebrae
structures in posterior mediastinum
- esophagus and its associated nerve plexus
- thoracic aorta and its branches
- azygos system
- thoracic duct
- sympathetic trunks
- thoracic splanchnic nerves
