7: Mediastinum Flashcards Preview

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Flashcards in 7: Mediastinum Deck (29):

what does mediastinum mean

that which stands between
(btwn 2 pleural cavities)


anterior mediastinum contents and borders

from sternum to pericardial sac; below sternal angle

lymph node, branches of internal thoracic vessels, lower part of thymus remnant


what covers much of internal anterior thoracic wall

costal reflections of parietal pleura


middle mediastinum

pericardial sac and contents AND phrenic nerve and cardiacophrenic vessels

**origin of internal thoracic artery and vein


posterior mediastinum, 8 major items

1. descending aortic arch
2. right posterior intercostal arteries
3. azygous system
4. esophagus
5. vagus nerve (plexus, vagal trunk)
6. long thoracic duct
7. esophagus
8. Sphlanchnic nerves


where is esophagus

immediately posterior to trachea and then pericardial sac; to right of aorta and then crosses over and is to tthe left at the esophageal hiatus (T10) to get to stomach, on left.


where is vagus nerve

behind root of lung, just outside esophagus, anastomoses to form esophageal plexus which forms vagal trunks

posterior--right vagus
anterior--left (PRAL)


descending aorta location

left side, then goes more right farther down

T12 -- with right posterior intercostal arteries and azygous system


thoracic duct location

starts at cisterna chyli, comes up through AORTIC hiatus, goes anterior to bodies of thoracic vertebrae and posterior to esophagus

**look left of azygous vein and right of esophagus


azygous system

forms collateral pathway between SVC and IVC

azygous vein/arch on right side; arches around behind hilus of lung of lung (that is posterior to SVC) and feeds into SVC to get blood into right atrium

accessory hemi azygous does top half of left; hemi azygous bottom half of left


vagus vs phrenic nerve

vagus: posterior to hilus of lung

phrenic: anterior to hilus of lung


sphlanchic nerves

from sympathetic chain ganglia


anterior longitudnal ligament

on anterior side of vertebrae

prevent excessive movement

most posterior part of pasterior mediastinum


locations of 3 hiatuses

1. cava: T8, IVC, highest and most central
2. aortic: T12 - aorta, azygous, thoracic duct
3. esophageal: T10 - esophagus, vagal nerves

ALSO dont forget, anterior, little holes for superior epigastric


10 items of superior mediastinum

1. infrahyoid muscles
2. thymus gland remnant
3. phrenic nerve
4. arch of aorta
5. vagus nerve
6. left recurrent larygenal nerve
7. esophagus
8. trachea
9. thoracic duct
10. braciocephalic veins


lateral borders of superior mediastinum

pleural sacs


infrahyoid muscles

sternohyoid closest to sternum (goes to hyoid bone)
then sternothyroid more medial (goes to thyroid cartilage)


braciocephalic veins

they come together on the right to form SVC; first, jugular comes to meet each from neck and then left courses over horizontally and meets right to make SVC


what does vagus go behind

root of lung


aortic arch

brachiocephalic artery on right; left common carotid and left jugular

***ligamentum arteriosum connects pulmonary trunk to aortic arch


ligamentum arteriosum

connects pulmonary trunk to aorta arch, remnant of ductus arteriosus

landmark for left recurrent laryngeal



C shaped hyaline cartilage; behind aorta and anterior to esophagus; no cartilage in the back
bifurcates at sternal angel


ascending aorta --> arch of aorta


passes over right pulmonary artery and left main bronchus


trachea anterior to what



what does phrenic nerve follow

the vertical axis of SVC (right) and then keeps going down, on left, between aorta and left BC vein;

more lateral than vagus, which goes between common carotid and jugular


right and left vagus nerve path

anterior to right subclavian artery; passes behind right BC vein

left: comes along carotid, anterior to aortic arch, behind pulmonary artery and hilus of lung (recurrent laryngeal)


end goal of thoracic duct

drains at jxn of left subclavian and jugular veins


path of thoracic duct in superior

moves to left of esophagus (bc going to jxn of left subclavian vein and jugulaR)


diaphragm blood supply

pericardiacophrenic a and musculophrenic vessels

(interior surface gets supply from aortic branches; IVC)