Mediastinum Flashcards
Superior mediastinum borders
extends from an oblique plane thru the jugular notch and T1 vertebra to a horizontal plane thru sternal angle and T4/5 IV disc inferiorly
Inferior mediastinum border
From sternal angle and t4/5 IV disc to the diaphragm. It is subdivided into the anterior middle and posterior regions
Superior mediastinum contents
Thymus, GREAT vessels, vagus and phrenic nerves, Trachea, Esophagus, Thoracic Duct.
Thymus location?
Root of neck superior and anterior mediastinum. Its the most anterior part of the superior mediastinum
Great arteries
Arch of aorta, from right to left they are the:
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
Great Veins
R and L Brachiocephalic vein (come off of SVC) and SVC
Where is the aorta
it begins at the level of the sternal angle, posterior to 2nd right sternocostal joint. (not covered by pericardium)
Where does the aortic arch ascend to before being directed posteriorly?
anterior to the right pulmonary artery and trachea
What is the aortic arch continuous with? It passes posterior to root of left lung
With the descending thoracic aorta
What does the Brachiocephalic trunk branch into?
right common carotid artery and right subclavian artery
What does the left common carotid artery branch into?
it doesn’t
Does the left subclavian branch?
no
What forms the Left and Right brachiocephalic veins?
The union of the internal jugular and subclavian veins
Where does the union of the internal jugular vein and subclavian vein happen?
posterior to the Sternoclavicular joints
Brachiocephalic veins unite to form the ____ at the level of the 1st costal cartilage (right)
Superior Vena cava
The SVC terminates at the level of the 3rd costal cartilage, but where does it pass into the middle mediastinum?
At the sternal angle
where does the SVC take blood from?
From structures superior to the diaphragm, except not the heart and lungs
Does the left vagus in the superior mediastinum pass posterior or anterior to the L Brachiocephalic vein?
Posterior
Does the left vagus pass anterior or posterior to the aortic arch?
anterior
Does the left vagus pass anterior or posterior to the root of the lung?
posterior
The left vagus contributes to
pulmonary plexus, esophageal plexus, and anterior vagal trunk
Where does the left recurrent laryngeal nerve go?
it passes around aortic arch, then ascends between the trachea and esophagus to reach the larynx
Does the RIGHT vagus pass anterior or posterior to the brachiocephalic vein?
posterior
Does the RIGHT vagus descend posterior or anterior to the SVC as it runs along the right margin of the trachea?
posterior
Does the RIGHT vagus pass posterior or anterior to the root of the lung while it is in the posterior mediastinum?
posterior
In the posterior mediastinum what does the RIGHT vagus contribute to?
pulmonary plexus, esophageal plexus, posterior vagal trunk
Where is the right recurrent laryngeal nerve?
its a branch in the neck
Where do sensory branches of the phrenic nerve go?
pericardium, mediastinal pleura and diaphragm
Do R and L p hrenic nerves pass anterior or posterior to the subclavian artery
anterior
do the R and L phrenic nerves pass anterior or posterior to the subclavian vein before entering the superior mediastinum?
posterior
Pericardiacophrenic vessels travel with the phrenic nerves, they are 3 structures, do they pass anterior or posterior to the root of the lung before descending thru the middle mediastinum between the fibrous pericardium and mediastinal pleura?
anterior
Where do trachea and esophagus originate?
at C6
where do trachea and esophagus go after passing thru the neck?
to the superior mediastinum
The trachea courses anterior to the esophagus and ends at the sternal angle, does it extend to the inferior mediastinum?
no
Where does the esophagus start and end
It starts at C6, goes to superior mediastinum, to the inferior mediastinum to reach the diaphragm, it ends at T11
What does the thoracic duct do?
conveys most lymph of body to the venous system(but not upper right quadrant)
The thoracic duct extends from the cisterna chyli (T12) to the
root of the neck
The thoracic duct ascends through the posterior mediastinum posterior to the esophagus, between the ____ and the ___
descending thoracic aorta and the azygous vein
Along its course the thoracic duct takes an oblique course to the left, enters the superior mediastinum, where it passes to the junction of the _____ and _____ where it terminates
left subclavian vein, and left IJV
Is the anterior mediastinum the largest or smallest subdivision?
smallest
What are the anterior and posterior boundaries of the anterior mediastinum?
The body of the sternum and the pericardium
What are the contents of the superior mediastinum?
thymus (which also extends into anterior) loose connective tissue and fat, lymphatic vessels and lymph nodes, mediastinal branches of the internal thoracic vessels
what are the contents of the posterior mediastinum?
Thoracic duct, esophagus and esophageal plexus, thoracic aorta, azygous and hemiazygous vein, sympathetic chain, greater, lesser and least splanchnic nerves
Where does the thoracic aorta begin and terminate?
begins at T4/T5 IV disc, and terminates at T12 vertebral level (where it enters abomen thru aortic hiatus)
What are the significant branches of the Thoracic aorta?
Posterior intercostal arteries, esophageal arteries, bronchial arteries, mediastinal branches, pericardial branches, superior phrenic arteries
Is the thoracic aorta to the left or right of the esophagus as it courses down?
to the left
Where do the azygous veins receive blood from?
From Body wall and mediastinal viscera
where does the azygous vein generally start?
At L1 level
As the azygous vein ascends through posterior mediastinum, is it positioned to the right or left of the thoracic duct?
to the right
What does the Azygous vein arch over to get to the SVC?
over the root of the right lung?
What the fukc is up with the hemiazygous vein and accessory hemiazygous vein?
they are on the left, and usually empty into the azygous vein but they are variable
The R and L sympathetic chain pass along the length of the ______ mediastinum
posterior
What are the three thoracic splanchnic nerves?
Greater, lesser and Least
Greater splanchnic nerve spinal levels?
T5-T9
Lesser Splanchnic nerve spinal level?
T10-T11
Least splanchnic nerve spinal levels?
T 12
