Mediastinum Flashcards
pulmonary cavities
lateral, lie on either side of the mediastinum
mediastinum and divisions
central compartment
superior
inferior
inferior has 3 - anterior middle and the posterior
superior mediastinum
from oblique plane through jugular notch and T1 vertebrae (superiorly) to a horizontal plane through the sternal angle and T4/T5 intervertebral disc (iv) inferiorly
ends at the sternal angle
inferior mediastinum
from sternal angle and T4/T5 (IV disc) superiorly to the diaphragm inferiorly
Thymus
Superior and anterior mediastinum
most anterior structure in the superior mediastinum as it is immediatley deep to the manubrium
primary lymphoid organ
Begins atrophy after puberty
Great vessels (arteries and veins) just list them
Great arteries
- Arch of aorta
- Brachiocephalic trunk
- left common carotid
- left subclavian (left because heart is offset to the left)
Great veins
R and left brachiocephalic veins
Superior vena cava
aortic arch is a continuation of…
and describe its region
continuation of ascending aorta
begins at the level of the sternal angle (2nd sternocostal joint)
ascends anterior to RIGHT pulmonary artery and trachea (before going posterior)
continuous with the descending thoracic aorta (which passes posterior to root of left lung)
aortic arch branches
brachiocephalic trunk (1st branch) - Right common carotid
Right subclavian
left common carotid - 2nd branch
left subclavian- 3rd branch
branches of the brachiocephalic trunk
right common carotid
right subclavian
T/F the aortic arch is anterior to the right pulmonary artery but posterior to the left pulmonary artery
TRUE
what forms the right and left brachiocephalic veins and what do they unite to form?
The right and left brachiocephalic veins are from the union of the right and left subclavian and internal jugular vein
they will form the superior vena cava -drain into heart
SVC is fromed at what level from what
where does it end?
Superior vena cava is formed at the level of the first costal cartilage (in superior mediastinum) and then descends at level of 3rd costal cartilage
(*passes into the middle mediastinum at sternal angel/2nd costal cartilage)
The SVC is formed from the right and left brachiocephalic veins which are formed from the R and L internal jugular vein and the R and L subclavian vein
function of SVC
returns blood from structures superior to the diaphragm
except the heart and lungs
left recurrent laryngeal nerve
as left vagus nerve passes anterior to the aortic arch it gives off the left recurrent laryngeal nerve- it passes around the aortic arch, before ascending between the trachea and esophagus to reach the larnyx
location of vagus in the superior mediastinum
anterior to the aortic arch
location of vagus in realtion to lung
posteiror - now in the posterior mediastinum
vagus contributions
pulmonary plexus (lungs)
inferiorly to esophageal plexus
anterior to vagus trunk (main)
right vagus nerve contribution to the vagal trunk
posterior vagal trunk (left vagus does more anterior vagal trunk)
course of right vagus
in superior will descend posterior to the superior vena cava and along the right margin of the trachea and will pass to the posterior aspect of the lung (posteiror mediastinum)
what level do the esophagus and trachea originate at?
C6
what level does the esophagus end
T11- goes out of the diapgragm at t10
when does the trachea end?
at the sternal angle- so does not pass into the inferior mediastinum
thoracic duct drains?
conveys most lymph of body to venous system except Right upper quadrant - right neck, upper extremity
extension of the thoracic duct
from t12 at the cistyerni chyli to the neck
important branches off of the thoracic aorta
superior phrenic arteries posterior intercostal arteries esophogeal arteries bronchial arteries pericardial branches
posterior mediastinum
portion of thoracic duct (rest in superior) - goes from t12 up into neck at the junction of the internal jugular vein and the left subclavian
esophagus + plexus
thoracic aorta -after arch to t12
azygous and hemiazygous
sympathetic chain (thoracic portion)
greater, lesser, and least splanchnic nerves
sensory innervation of the phrenic nerve
sensory to the pericardium, mediastinal pleura, and the disphragm
course of the phrenic nerves in the superior mediastinum
anterior to the subclavian arteries and posterior to the subclavian veins - then enter the superior mediastinum
course of pericardiacophrenic vessels
these travel with the phrenic nerves and with the phrenic nerves will take an anterior course over the lungs and descend into the middle mediastinum BETWEEN THE FIBROUS PERICARDIUM AND THE MEDIASTINAL PLEURA
Contents of the anterior mediastinum
thymus
lyphatic vessels and lymph nodes
mediastinal branches of the internal thoracic vessels
loose connective tissue
smallest subdivision
sternum - anterior with pericardium posteriorly
