Lecture 15 - Superior and Posterior Mediastinum Flashcards
What separates the the post/ant mediastinum from the superior mediastinum
The bottom of the manubrium
What distinguishes the ant/post mediastinum and inferior
Top of the xiphoid process
What spinal segments are associated with the posterior mediastinum
T5-12
Where is the jugular notch
T2 in men and T3 in women
What joins to form the brachiocephalic vein
Subclavian and internal jugular
At what level is the trachea bifurcation and the beginning of the aortic arch
T4
Where do the phrenic nerves run in relation to the lung
Anterior
Where does the vagus nerve run
Posterior
What does the left recurrent laryngeal nerve go
Hooked around the ligamentum arteriosum
What nerves are involved in MI
Cardiac pain via left sympathetic nn and BP and O2 sensors via vagus n
What are the branches supposed to be off of the aortic arch
- Brachiocephalic trunk branches into R common carotid and R subclavian
- L common carotid
- L subclavian
What do the brochial AA supply
They go into the hilum of the lungs and supply primary, secondary, and tertiary brochioles
What do superior phrenic A supply
Diaphragm
What drains the R posterior thorax
Azygos v
Where is the hemiazygos v
Below T9 on the left side where it crosses behind the esophagus and dumps into azygos v
What are the branches of the internal thoracic A
Pericardiacophrenic A
Superior epigastric A (terminal)
Musculophrenic A (terminal)
What does the thoracic aorta give rises to
Superior phrenic AA
What are the 3 parts of the esophagus
Cervical (C6-T1)
Thoracic (T1-diaphragm hiatus)
Abdominal
What does the esophagus pierce
Left posterior diaphragm
What are the common constriction sites for the esophagus
Cricopharyngeus muscle in cervical region (C6)
Aortic arch (T4)
Left bronchus
Diaphragm (T10)
Around the esophagus what nerve travels laterally? Where does it end up
Vagus N.
The L Vagus goes anterior
R Vagus goes posterior
At what levels are the greater splanchnic NN
T5-9 presynaptic sympathetic fibers
Pass anteriorly through the diaphragm to relay in celiac ganglion
What level are the lesser splanchnic nn
T10-11
Where are the least splanchnic nn
T12
What are thoracic splanchnic nn
Sympathetic presynaptic ganglion
What are the gray communicans
Unmyelinated neurons
What are white rami
Myelinated neurons
Where does the right thoracic duct dump into
Right subclavian v
Where does the thoracic duct dump into
L subclavian V
Where does the thoracic duct run
Between azygos v and descending aorta
Where does the thoracic duct terminate
Near the junction of the internal jugular v and subclavian v
What can impinge on the vagus n
Mediastinal lymph nodes (lung cancer)
Impinging on the left recurrent laryngeal n can cause
Hoarseness which can disrupt speech
What keeps the ductus arteriosus open during development
Prostaglandins
What normally causes the ductus arteriosus to close
Changes in o2 tension and blood flow decrease prostaglandin levels which cause SM to contract around 10-15H
What are the consequences of PDA
LV hypertrophy with pulmonary congestion and congestive heart failure
What causes an increased risk of PDA
Maternal rubella infection
Where do we see more coarctation
Turner’s syndrome
What is an aberrant origin of the right subclavian
Doesn’t come off brachiocephalic trunk instead comes off on the left most position and comes behind the esophagus
What can occur with the R aortic arch
It can persist after development causing a double aortic arch
Where are interrupted aortic arches more common
DiGeorge Syndrome
What is a disrupted aortic arch
The left and right aortic arches degenerate so the L and R trunks are separate
Where do the common carotid come from
The third aortic arch
Where does the mature aortic arch come from
L 4th aortic arch
Where does the left subclavian come from
7th intersegmental aortic arch
What does the left recurrent laryngeal n get hooked to
Ligamentum arteriosum
The R recurrent laryngeal gets hooked to the
R subclavian A
Is preductal coarction or postductal worse?
Preductal, b/c postductal can still provide blood via collateral system through the L subclavian A which then connects to the internal thoracic A and intercostal A to the lower limb
What can an aberrant R subclavian cause
Dysphagia since it wraps around the esophagus posteriorly
