Mediastinum Flashcards
Name a few things found in the superior mediastinum.
Thymus gland Superior Vena Cava Arch of aorta Vagus and phrenic nerves Trachea and esophagus Thoracic duct
Where is the thymus gland located?
Posterior to the manubrium but anterior to the brachiocephalic vein
When is the thymus gland active?
During childhood prior to puberty
Functionally inactive in adults- atrophy results
Which brachiocephalic vein crosses the trachea anteriorly?
The left brachiocephalic vein
At what level does the aortic arch begin and end?
T4-T5 (sternal angle)
What does the aortic arch arch over?
It arches over the Left main bronchus and pulmonary trunk
What are the three arteries that arise from the aortic arch?
Brachiocephalic trunk
Left common carotid
Left subclavian artery
T/F the vagus nerve descends posterior to the root of the lung?
True
The vagus supplies what kind of innervation to the thorax?
Parasympathetic
The phrenic nerve descends _____ to the root of the lung.
Anterior
The phrenic nerve supplies _____ innervation to the diaphragm.
Somatic
The phrenic nerve comes from which spinal levels?
C3-5
Where is the trachea in relation to the esophagus?
It is immediately anterior to i
Where does the trachea bifurcate?
At the inferior limit of the superior mediastinum
T/F numerous lymph nodes are found at the carina?
True
What is the carina?
It is the ridge that denotes the bifurcation of the trachea into right and left main bronchi
Foreign bodies are usually aspirated into which main bronchus? Why?
The right one
It’s more vertically oriented and is shorter and WIDER than the left main bronchus
Where is the carina usually positioned in regards to the median plane?
Just to the left of it
The esophagus descends _____ to the trachea
immediately posterior
Where does the esophagus pierce the diaphragm?
At the esophageal hiatus
The esophagus empties into where?
the stomach
T/F the stomach may herniate through the esophageal hiatus?
Truth
What is a type I sliding hiatal hernia?
It is where the stomach slides freely into the thorax- this is the most common and is often asymptomatic
What is a type II paraesophageal hernia?
It is where the fundus has basically escaped through the esophageal hiatus and is stuck up next to the esophagus- can risk gastric blood supply
What is found in the posterior mediastinum?
Esophagus and esophageal plexus Azygos system veins Descending aorta Thoracic duct Thoracic splanchnic nerves
The esophageal plexus is made from what?
The joining of the vagus nerves.
The left vagus nerve forms the ____ vagal trunk and the right vagus nerve forms the _____ vagal trunk.
Anterior
Posterior
The azygos system of veins provides venous drainage for what?
The thorax
The azygos vein drains what?
intercostal veins from the right side of the thorax
The hemiazygos and accessory hemiazygos veins drain what?
The left thorax
What do the the hemiazygos and accessory hemiazygos veins drain into?
The azygos vein
The azygos vein arches over what to drain into what?
arches over the Right superior bronchus to drain into the superior vena cava
In relation to the esophagus, where does the descending aorta lie?
just left of the esophagus
What does the aorta supply and give rise to (via branches)?
gives rise to the posterior intercostal arteries supplying the thorax and supplies branches to the trachea, bronchi, and esophagus
Where does the thoracic duct lie?
It lies posterior to the esophagus and anterior to the vertebral bodies
The thoracic duct is located between the _____ vein and the _____ _____.
azygoes vein
descending aorta
The thoracic duct drains lymph from where?
The entire body below the diaphragm
Where does the thoracic duct enter the venous angle?
Between the left sublcavian vein and the left IJV
What is a chylothorax?
The accumulation of lymph in the pleural cavity
How does one go about getting a chylothorax?
Tear your thoracic duct- often from a trauma during surgery or a lymphoma
is chylothorax visible on chest films?
yes
What are the two types of branches from the sympathetic chain ganglia?
1st branch- postganglionic sympathetics to thoracic viscera
2nd branch- preganglionic sympathetic to the abdomen, not the thorax
What are the three nerves that come off the 2nd branch type of the chain ganglia?
greater, lesser, and least splanchnic nerves
For thoracic autonomics, from which spinal levels do sympathetics originate from?
T1-T5
For thoracic autonomics, from where do parasympathetics originate from?
CN X
The sympathetics and parasympathetics intermingle to form 3 thoracic plexuses- what are they?
Cardiac
Pulmonary
Esophageal
