Contents of the mediastinum Flashcards
what is contained in the superior mediastinum?
BATS & TENT
Brachiocephalic veins
Arch of aorta
Thymus
Superior vena cava
Trachea
Esophagus
Nerves (vagus & phrenic)
Thoracic duc
what is contained in the posterior mediastinum?
DATES
descending aorta
azygous vein and hemiazygous vein
thoracic duct
esophagus
sympathetic trunk/ganglia
what is contained in the anterior mediastinum?
thymus gland
hard to see in dissection
what is contained in the middle mediastinum?
heart
where is the posterior mediastinum located?
behind the pericardial sac
behind the left atrium which is the posterior border of the heart
where is the thymus gland?
immediately behind the manubrium
in the anterior mediastinum
after puberty, largely turns into fat
where are the trachea and esophagus?
fill the superior thoracic aperture in the median plane between the apices of the lungs
what is anterior the trachea or esophagus?
trachea is anterior to esophagus
where does the trachea bifurcate?
behind sternal angle
where is the aortic arch?
right border of the sternal angle
where do the subclavian arteries and veins go?
into the upper extremities
3 branches of the aortic arch
Brachiocephalic trunk (which divides into R suclavian and R common carotid)
Left common carotid (enters neck behind the left sternoclavicular joint)
Left subclavian artery
what makes the brachiocephalic veins?
union of the subclavian and internal jugular veins
come together behind the R and L sternoclavicular joints
what forms the superior vena cava?
the union of the R and L brachiocephalic veins
what also empties into the superior vena cava?
the azygous vein
brachiocephalic veins
what empties into the azygous vein?
posterior intercostal veins
where do posterior intercostal Arteries arise from?
the thoracic aorta or 2 from the subclavian
how many vagus nerves are there?
2
where are the vagus nerves?
behind the root of the lungs
Left recurrent laryngeal nerve
hooks around the left side of the arch of the aorta behind the ligamentum arteriosum
ascends in a groove between the trachea and esophagus
is the right recurrent laryngeal nerve found in the mediastinum?
NO
how can you tell the difference between phrenic and vagus nerves?
phrenic nerves descend in FRONT of the lungs
also longer as they go to the diaphragm
what is the esophagous a continuination of?
the pharnynx
where is the esophagus?
in the superior and posterior mediastinum
behind the trachea
which way does the esophagus lean?
lean towards the left
goes behind the left atrium and then crosses in front of the aorta
Esophageal constrictions, list them superior to inferior
a. Where the pharynx joins the upper end
b. Where it contacts the arch of the aorta
c. Where it contacts the left principal bronchus
d. The esophageal hiatus of the diaphragm
what forms the esophageal plexus?
the vagus nerve reaches the esophagus
the nerve then breaks into several trunks
what side of the sternal angle is the descending aorta on?
the left side
thoracic branches of the descending aorta
a. Lower nine posterior intercostal arteries
b. Subcostal arteries
c. Bronchial arteries
d. Esophageal arteries
e. Superior phrenic arteries
what does the azygous venous system do?
drains blood from the body wall
also receives some blood from the intercostal veins
if the main venous channel from lower parts of body is blocked, how can blood return to the heart?
through the azygous vein
what does the azygous vein split into?
the hemiazygous vein on the left
what type of vessel is the venous thoracic duct?
a lymphatic vessel
where does the thoracic duct begin?
in the abdomen
aortic hiatus
midline opening in posterior diaphragm to allow descending aorta, thoracic duct, and azygous / hemiazygous veins to pass through
where is the thoracic duct?
on the right side of aorta
between aorta and azygous vein
where does the thoracic duct empty?
left subclavian / internal jugular veins
coarctation of the aorta
aortic arch is abnormally narrow
blood must flow around vessels before the constriction
what becomes important in coarctation of the aorta?
anatomases between anterior and posterior intercostal arteries
how does blood flow in coarctation of the aorta?
subclavian arteries
internal thoracic artery
anterior intercostal artery
posterior intercostal artery (backward flow)
descending aorta
What is tumor at apex of lung called?
Pancoast tumor
Results of Pancoast tumor
impinge the brachial plexus
tumor impacts the sympathetic trunk leading to Horner syndrome
Horner syndrome
Ptosis (drooping of the eyelid)
* Miosis (constricted pupil)
* Anhidrosis (inability to sweat)
thoracic outlet syndrome
superior thoracic aperture / thoracic outlet becomes compressed similar to in a pancoast tumor
