superior/posterior mediastinum Flashcards
what defines the region of the superior mediastinum
above the sternal angle.
largest features of the superior mediastinum
great vessels and the trachea
primary branches from the aorta
1st right subclavian artery and right common carotid artery
2 left common carotid artery
3. left subclavian artery
regions of the superior mediastinum and contents of each region
retrosternal (veins): thymus, left branch of brachiocephalic v, superior part of the SVC
- intermediate (arteries): aortic arch, brachiocephalic trunk, left common carotid a, left subclavian a
- Pre-vertebral (visceral): trachea, esophagus, left recurrent laryngeal n.
cardiac plexus contains what type of autonomic fibers
pre ganglionic parasympathetic fibers
post ganglionic sympathetic fibers
phrenic nerves travel ____ to the root of the lung
anterior
vagus nerves travel ____ to the root of the lung
posterior
what happens at vertebral level t4/t5 with the trachea
bifurcates into primary bronchi
in a cross section of the superior mediastinum, what is more ant/posterior vagus nerves or phrenic nerves
phrenic nerves: anterior
vagus nerves: posterior
the aspect of the trachea facing the posterior esophagus is made of what? versus what makes up the arch?
the aspect of the trachea facing the esophagus is made of smooth muscle, to ease swallowing food when the esophagus expands. the arch of the trachea is made of cartilage.
what branch of nerves arise from the right and left vagus nerves
right and left recurrent laryngeal nerves
what does the right recurrent laryngeal nerve wrap around
the right subclavian a.
considered to be more in the root of the neck, vs the superior mediastinum
left recurrent laryngeal nerve loops around the
arch of the aorta and ligamentum arteriosum
what was the ligamentum arteriorsum called when it was a fetal shunt? what did this shunt connect
ductus arteriosus connects the aorta to the pulmonary trunk.
which branch of the recurrent laryngeal nerves has a shorter, more oblique course?
the right recurrent laryngeal nerve.
what is the phrenic nerve sandwiched between in the mediastinum
the mediastinal pleura and the fibrous pericardium
where is the posterior mediastinum
in the thoracic region, between the posterior wall of the pericardial sac and the posterior thoracic wall
the sternal angle is at what vertebral level
t4/t5
areas where the esophagus is narrowed?
the pharyngeal junction, aortic arch, tracheal bifurcation, esophageal hiatus of the diaphragm (t10)
how can an aortic aneurism make swallowing difficult
a bulge in the aortic arch can impinge on the esophagus. deviating or even constricting the esophagus making swallowing difficult.
how could an esophageal tumor cause troubled breathing
a bulge in the esophagus could push on the tracheal lumen causing labored breathing
why would a pancoast tumor cause horseness?
the right vagus nerve branches around the subclavian artery to form the right recurrent laryngeal nerve that supplies motor innervation to the larynx. this lies directly on the apex of the lung, a tumor would suppress this nerve causing horseness.
how does the left vagus nerve pass the aorta arch
? what does it contribute to
anteriorly, gives rise to the left recurrent laryngeal nerve posteriorly.
the left vagus nerve passes in what direction to the ligamentum arteriosum?
laterally
how would an aortic aneurism in the aortic arch, cause clinical presentation of horseness?
the bulge in the aorta would compress the left laryngeal nerve, which supplies motor function to the larynx (voice box)
where is the larynx found
the superior portion of the trachea, it is your voice-box that leads to your windpipe: trachea.
the vagal nerve contributes preganglionic parasympathetic fibers to what plexuses?
the esophageal plexus, pulmonary plexus, cardiac plexus.
visceral branches of the aorta
- paired bronchial arteries: supply primary and secondary bronchi
- esophageal arteries: arise from descending aorta and supply the length of the thoracic esophagus.
parietal branches of the aorta
- paired posterior intercostal arteries that supply intercostal spaces and body wall
- superior phrenic arteries: supply the diagraphgm
contents of the posterior mediastinum
hint: includes the 6 birds
- descending thoracic aorta
- sympathetic trunk
- splanchnic nerves
- esophagus
- azygous vein
- hemiazygous vein
- left vagus n
- right vagus n
9: thoracic duct
where do vagus nerves lie in a cross section of the posterior mediastinum
?
next to the esophagus.
where does the esophagus meet with the diaphragm?
t 10
what are the components of VAN and what are each derived from (right side)?
V: posterior intercostal veins: azygous vein
A: posterior intercostal arteries: aorta
N: intercostal nerves: sympathetic trunk
how are the components of VAN located? and where can they be found
vein is the superior aspect, the artery is between the vein and nerve, intercostal nerves are the most inferior and are least protected from the costal groove
in the intercostal space, more specifically in the intercostal groove
what does the azygous dump into and what is the common description of this area
superior vena cave: the hook looks like a candy cane
lymph of the right upper limb, right side of the neck, and the right thorax is drained via the
right lymphatic duct
lymph drainage percentage that the thoracic and right lymphatic ducts are responsible for
thoracic: 3/4
right lymphatic duct: 1/4
where does the right lymphatic trunk drain lymph into
the junction between the internal jugular vein and the right subclavian vein.
what does the thoracic duct drain lymph into
the junction between the left internal jugular vein and the left subclavian vein
where does the thoracic duct begin in the abdomen?
the cisterna chyli, where lymph from the abdomen and lower limbs collect before passing up through the thoracic duct.
the thoracic duct lies where in the posterior mediastinum?
posterior to the esophagus, between the aorta and azygous vein.
the cristerna chyli is ____ to the celiac trunk
anterior
the internal jugular vein and subclavian veins join to form the ____ before entering into the superior vena cava
brachiocephalic vein
pathway of lymph from the capillaries to the collecting ducts
capillary–> lymphatic vessels –> lymph nodes –> trunks –> collecting ducts (thoracic and right lymphatic duct)
posterior intercostal aa arise from?
anterior intercostal aa arise from?
descending thoracic aorta
internal thoracic artery
where do the anterior and posterior intercostal veins anastamose?
3/4 of the way forward through the intercostal space
the internal thoracic artery arise from the
subclavian arteries at the root of the neck.
the internal thoracic arteries are accompanied by ___ _____ venous arrangement below ___
venea commitantes, below rib 3
terminal branches of the internal thoracic aa
- musculophrenic a, superior epigastric a
what is the superior epigastric artery found on the back of
the back of rectus abdominis
the superior epigastric artery anastamoses with the _____ ____ ____ which is a branch of the ___ ___ ___ forming a potential collateral pathway to bypass the ___
inferior epigastric artery, external iliac artery, aorta
what do VAN enter and exit the intercostal space between
the innermost intercostal muscle and the internal intercostal m posteriorly.
there are ____ branches from VAN that run ____ in the intercostal space
collateral, lower
VAN lies directly ____ the ____, therefore it is best to insert a needle to drain fluid from the lungs ____ the ____. carefully of the collateral branches can be injured during aspiration.
under the rib,
above the rib
the intercostal space contains _ muscle layers and a ___
3 muscle layers: external, internal, innermost intercostals
and a neurovascular bundle (VAN)
the costal groove is on the ____ aspect of the rib, semi protecting VAN, but leaves the ____ the LEAST protected
the inferior aspect of the rib, leaves the intercostal nerve the least protected.
venous drainage of the thoracic and abdominal wall is _____ and ______
indirect and segmental
the azygous and hemiazygous veins receive venous drainage from
- posterior intercostal veins
- lumbar segmental veins
- superior intercostal veins
- bronchial, esophageal, and mediastinal vv.
anterior aspect of the thoracic wall is drained venously by the
anterior intercostal vv to the internal thoracic vv (which lie on either side of the internal thoracic aa)
azygous system drains each side _____ but the two halves join a pattern resembling a _____ _
separately but form a broken H
the venous drainage system on the left side is formed by the
hemiazygous v and the accessory hemiazygous vein
the venous drainage on the right side from the thoracic and posterior abdominal wall is done by the
azygous v
typically the hemiazygous v drains to the azygous v between __ and ___, while the accessory hemiazygous v drains to the azygous v at about ___
hemiazygous v : T8-T10
azygous v : T7
the superior intercostal v drains the upper __ and __ interspaces, on the left it drains to the ___ and on the right it drains to the ___
3/4 interspaces, left: brachiocephalic v, the right it drains to the arch of the azygous v.
ayzgous is located more on the ____ side of the body and hemiazygous v and accessory hemiazygous v are located on the ___ side of the body
right side,, vs the left side of the body.
the accessory hemiazygous is more ____ than the hemiazygous v
superior
