Superior and Posterior Mediastinum Flashcards
superior mediastinum border - anterior
manubrium
superior mediastinum border - posterior
bodies of T1-T4 vertebrae
superior mediastinum border - inferior
transverse thoracic plane
superior mediastinum border - superior
thoracic inlet
what is reflected over the structures of the mediastinum on either side of the superior mediastinum
parietal pleura
describe the contents of the superior mediastinum from anterior to posterior
- thymus
- brachiocephalic veins uniting to give SVC
- arch of aorta
- trachea
-oesophagus - phrenic and vagus nerves
- lymphatics
of the contents of the superior mediastinum what is not found in any other part of the adult mediastinum
thymus
brachiocephalic veins
arch of aorta
trachea
what lies directly posterior to the brachiocephalic veins draining into SVC
arch of aorta and branches
what are the 3 branches of the aorta
brachiocephalic trunk
left common carotid
left subclavian
what does the brachiocephalic trunk divide to give
right subclavian and right common carotid
describe the path of the right vagus nerve in the superior mediastinum
anterior to right subclavian artery
describe the path of the right recurrent laryngeal nerve
loops under the right subclavian artery then travels back up to larynx
describe the path of the left vagus nerve in the superior mediastinum
travels between left common carotid and left subclavian then passes along left side of arch of aorta
describe the path of the left recurrent laryngeal nerve
loops under arch of aorta (posterior to ligamentum arteriosum)
the vagus nerves give branches to what plexuses
cardiac plexus
right and left pulmonary plexus
where is the cardiac plexus
deep to arch of aorta
anterior surface of bifurcation of trachea // posterior aspect of ascending aorta
where are the pulmonary plexuses
on right and left main bronchi
the vagus nerves form what plexus
oesophageal plexus
how do the vagal trunks form
fibres of oesophageal plexus come together to form anterior and posterior vagal trunks that will continue into abdomen
the anterior vagal trunk is mostly comprised of fibres from the ___ vagus
left
the posterior vagal trunk is mostly comprised of fibres from the ___ vagus
right
what is the root of the phrenic nerves
anterior rami C3,4,5
(keep diaphragm alive)
describe the course of the right phrenic nerve
runs alongside right brachiocephalic vein, then SVC and then pericardium over right atrium
the right phrenic nerve passes _____ to root of right lung
anterior
where does the right phrenic nerve pierce the diaphragm
near caval opening
describe the course of the left phrenic nerve
lies between left subclavian artery and vein and continues to left of arch of aorta anterior to vagus
continues onto surface of pericardium over left atrium and ventricle
the left phrenic nerve passes _____ to root of left lung
anterior
where does the left phrenic nerve pierce the diaphragm
left of pericardium, near apex
where does the trachea begin
C6/7
below larynx
what is the point of division of trachea called
carina
what is the carina
V shaped cartilage that is the bifurcation of trachea
where is the carina
transverse thoracic plane (T4/5)
the trachea has C shaped cartilage (anteriorly/posteriorly)
anteriorly
what is found on the posterior surface of the trachea
trachealis muscle
what would be the issue if the trachea was completely cartilage
oesophagus (posterior to trachea) wouldn’t be able to expand to allow bolus of food through
where does the oesophagus begin
C6
the oesophagus is a continuation of the
pharynx
describe the course of the oesophagus in the superior mediastinum
travels in superior mediastinum immediately posterior to trachea
describe the course of the oesophagus in the inferior mediastinum
initially lies to right of aorta then crosses anteriorly prior to piercing the diaphragm
at what level does the oesophagus pierce the diaphragm
T10
what are the 3 constrictions of the oesophagus from
arch of aorta
left bronchus
diaphragm
boundaries of the posterior mediastinum: superior
transverse thoracic plane
boundaries of the posterior mediastinum: posterior
bodies of T5-T12 vertebrae
boundaries of the posterior mediastinum: anterior
posterior wall of pericardium and slope of diaphragm
what is on either side of the posterior mediastinum and reflected onto structures
parietal pleura
when does the arch of aorta become thoracic aorta
continuation of arch of aorta at level of transverse thoracic plane (T4/5)
when does thoracic aorta become abdominal aorta
after passing through aortic hiatus of diaphragm
thoracic aorta gives branches to
oesophagus
pericardium
bronchi
thoracic wall
diaphragm
what drains the thoracic wall
azygous vein
where is the azygous vein
posterior mediastinum
on the right side of the thoracic wall, posterior intercostal veins 2-11 and subcostal drain where
directly into azygous vein
on the right side of the thoracic wall, the 1st posterior intercostal vein drains where
directly to right brachiocephalic vein
on the left side of the thoracic wall, the 1-4 posterior intercostal veins drain where
left brachiocephalic vein
on the left side of the thoracic wall, the 5-8 posterior intercostal veins drain where
accessory hemiazygous
on the left side of the thoracic wall, the 9-11 posterior intercostal veins and subcostal drain where
hemiazygous
the hemiazygous and accessory hemiazygous go where
to azygous vein
azygous vein drains where
SVC
left posterior intercostal veins drain in groups of _ to left brachiocephalic vein, accessory hemiazygous and hemiazygous
4
(1-4)
(5-8)
(9-11 + subcostal)
what is the major lymphatic vessel in the thoracic region
thoracic duct
the thoracic duct drains what
all of the lymph from the lower limbs, pelvis and abdomen and from left side of thoracic cavity
where does the thoracic duct join the venous system
at the left venous angle
where is the left venous angle
junction of left internal jugular vein and left subclavian
where is the thoracic duct located
between thoracic aorta and azygous vein on surface of bodies of thoracic vertebrae
what is the sympathetic chain
chain of sympathetic ganglia extending the length of the vertebral column on either side
where does sympathetic outflow come from
T1-L2/3
what can be seen in the thoracic region of the sympathetic chain
both white and grey rami communicantes travelling between the spinal nerves and the sympathetic chain
what are white rami communicantes
myelinated nerves travelling from spinal cord into the sympathetic chain
what are grey rami communicantes
post-ganglionic non-myelinated fibres passing from chain into spinal nerve to be distributed to body wall
how many splanchnic nerves are there and what are their names
3 either side
- greater, lesser and least
what do the splanchnic nerves supply
sympathetic innervation to the abdominal viscera
the splanchnic nerves will pass through the _____ to be distributed in the abdominal cavity
diaphragm
what do the splanchnic nerves carry
pre-synaptic sympathetic fibres for abdominal viscera
describe the course of the splanchnic nerves as they pass through the diaphragm
synapse in ganglia assoc. with the aorta
where does the greater splanchnic nerve receive fibres from
T5-T9 ganglia
greater splanchnic nerve assoc. with what ganglia
coeliac and superior mesenteric
where does the lesser splanchnic nerve receive fibres from
T10 and T11
the lesser splanchnic nerve assoc. with what ganglia
superior mesenteric and aorticorenal
where does the least splanchnic nerve receive fibres from
T12 ganglion
what ganglia does the least splanchnic nerve assoc with
aorticorenal
what is the broad tendinous region in the centre of the diaphragm called
central tendon of the diaphragm
what opening in the diaphragm allows the passage of the IVC
caval opening
what does the oesophageal hiatus allow the passage of
oesophagus and assoc. vagus nerves
where is the oesophageal hiatus located
within muscle of left crus
what does the aortic hiatus allow the passage of
aorta
thoracic duct
azygous vein
where is the aortic hiatus
space posterior to the median arcuate ligament
at what level does the IVC pierce the diaphragm
T8
at what level does the oesophagus and vagal trunks pierce the diaphragm
T10
at what level does the aorta pierce the diaphragm
T12
how and at what level do the greater and lesser splanchnic nerves pierce the diaphragm
T12
small openings in the crura
how and at what level does the least splanchnic nerve and the sympathetic trunk pierce the diaphragm
T12
posterior to medial arcuate ligament
why does the right dome often bulge more superiorly
overlies the liver
