superior and posterior mediastinum Flashcards
divisions of the mediastinum
Superior Inferior - anterior - middle -posterior
where does the mediastinum extend
From the thoracic inlet to the diaphram and sternum to 12th vertebra
what is foudn in the superior mediastum
Thymus gland (anterior)
SVA and great vv (R and L brachiocephalic V)
Arach of aorta and great aa (Brachiocepahlic trunk, left common caroitd, left subclavian )
Vagus nn
Phrenic nn (anterio)
Left recurrant laryngeal( if above the the aortic arch)
trachea
Esophagus (posterior)
THoracic duct
what does the thymus gland sit posterior to
Manubrium
what does the thymus gland lie anterior to
Brachiocephalic vv
when is the thymus gland most active
childhood
what happens to the thymus gland in adults
Inactive and may appear as a fatty mass as it atrophies
what drains into the SVC
Right and left brahiocephalic veins
azygous vein
how does the L brachiocephalic v cross the trachea
Anteriorly (in addition to being anterior to the 3 great arteries along with nerves)
where does the azygous vein drain superior to
The Right bronchus (root of right lugn)
where does the aortic arch begin and end
At the same level, sternal angel, t4-5
parts of the aorta
ascending
arch
desceding
what part of the aorta is in the superior mediastinum
the arch
what part of the aorta is in the interior mesiastium
the ascending and descending portions
what part of the middle mediastinum does the ascending aorta come from
The middle
what does the aortic arch, arch over
L main bronchus and pulmonary Trunk (R pulmonary A)
what arties goes the aortic arch give off
Brachiocephalic trunk
L common carotid A
L subclavian
what does the vagus nerve and phrenic nerve pass through the thoracic inlet betwen
a vein and artery
Vegus in relation to the root of the lung
Posterior to the root (anterior to aortic arch tho)
what does the Vagus do for the thorax and ab
Parngasympathetic innervation
relation of phrenic nerve to the root of lung
Anterior to the root of lung (very anterior))
roll of phrenic nerves
Somatic innervation to diaphram (motor and sensory)
phrenic nerve comes from what
C3-C5 (C3 4 and 5 keep me breathing and alive)
what parts of the diaphram does the phrenic nerve serve
The superior and inferior portions
how does the R and L phrenic nerve reach the inferior portion of the diaphram
R Through the hiatus of the IVC at T8
L: through diaphram at the apex of the heart margin of central tendon with muscle
where is the trachea
Immediately anterior to esophagus
where does the trachea bifurcate
At inferior limit of superior mediastinum
the gooch of the trachea
Carina
where are a lof of lymph nodes found in the trachea
at the carina
where does the trachea bifurcate
T4/5
the inferior extent of the superior mediastum
Carina
where are foreign bodies usually aspirated and why
R main bronchi because it is shorter, wider, more verticle
Carina is usually positioned L of median plane
where does the esophagus begin
In the kneck below the pharynx. inferior margin of cricoid cartilage
what does the esophagus descend behind
Posterior to trachea
where does the esophagus pierce the diaphram
Esophageal hiatus
arteries of the esophagus arise from
Thoracic aorta, bronchial aa, and ascending L gastric A
Venious drainage of teh esophagus
Azygous
Hemiazygous
L grastric
lymphatics of esophagsu
Posterior mediastinum
where might the stomach herniate
Through the esophogeal hiatus
when the stomach herniates through the esophogeal hiatus
Hiatal hernia
what is a sliding hiatal hernia
Type I
what happpens in a sliding hiatal hernia
Somach slides freely into thorax
Asymptomatic
Commonness of sliding hiatal hernia (type I)
Most common
what is a paraesophageal hernia
type II
where does a paraesophageal hernia pass through
The fundus
what problesm occur with a type II hernia
Fixed in position risking gastric blood supply
uncomfortable
where is the retropharyngeal space
Behind the buccopharyngeal fascia and the prevertebral fascia(alar layer)
other name for the retropharyngeal space
Danger space
how far down does the retropharyngeal space go
t12
what is found in the posterior mediastinum
Esophagus Esophageal plus Azygous system of vv Descending aorta Thoracic duct Thoracic splanchnic nn ( pre ganglionic sympa)
what forms the plexus around the esophagus
Vagus nerve
what happens to vagas nerve near disaphragm plexus
REforms Vagal runks
What is the L vagus N
Anterior vagal trunk
what is the R vagus N
Posterior Vagal trunk
what does the L and R vagus N becomes anteror and posterior trunks
Due to rotation of gut during development
where do both trunks pass through with the esophagus
through the diaphragm
what provides venous drainage for thorax
The azygos system of veins
what does the azygous vein drain
Intercostal vv from R side of thorax
what does the hemiazygous and accessory hemiazygous vv drain
L thorax
what does the hemiaxygous and accessory hemiazygous drain into
Azygous V
how does the Azygous v drain into the SVC
Arches over the R superior bronchus
what more superior, hemiazygous or accessory hemiazygous
Accessory is more superior
relation of the descending aorta to the esophagus
Just left of the esophagus
what does the descending aorta give rise to
Posterior intercostal aa supplying the throax
Branches to trachea, bronchi, and esophagus
location of the thoracic duct
Posterior to esophagus and anterior to vertebral bodies
Between azygous v and descending aorta (thorax)
in the mid line
where does the thoracic duct pass through the diaphram
With the descending aorta
what does the thoracic duct drain
Entire bod below diaphram
where does the thoracic duct enter the venous angel
Between L subclavian v and L IJV
taccumulationof lymph in the pleural cavity
Chylothorax
Chylothorax results from
Torn or leaking thoracic duct
what may cause a tear or leaking thoracic duct
Lymphom/trama during thoracic surgery
can you see chylothorax on chest films
YES
where are sympathetic trunks found
Lateral to vertebral bodies
How do sympa trunks get to ab
Pass posterior to diaphram thru cura to enter
Types of Branches from sympathetic chain ganglia
Postgang sympa to thoracic viscer
Preganglionic sympa to innervate the abodomen
(Greater, lesser, least splanchnic)
branches of the greater spanchnic
T5-9
Branches for the lesser splachnic
T10-11
Branches of least splanchnic
T12
Thoracic sympathetics originate from
T1-T5
Thoracic parasympathetics come from
CNX
Plexus of the thorax
Cardiac
Pulmonary
Esophageal
what makes up the thoracic plexues
both T1-5
and CNX