Organization of the Thorax and Overview of Cardiovascular System Flashcards
What are 3 cavities of the thorax?
Right pleural cavity
Left Pleural cavity
Mediastinum
What are the boundaries of the mediastinum?
Superior: Superior thoracic aperture
Inferior: Inferior thoracic aperture (diapragm)
Anterior: Sternum
Posterior: Thoracic vertebrae
Lateral: Pleura
A line running from the sternal angle to ________ divides the mediasinum into superior and inferior divisions.
T4-5
The ______________ further divides the inferior mediastinum into the anterior and posterior mediastinum.
Pericardial sac
What are the contents of the superior mediastinum?
Arch of Aorta
- Brachiocephalic artery
- Left Common carotid artery
- Left Subclavian artery
Superior Vena Cava
- Brachiocephalic veins
- Left superior intercostal vein
- Supreme intercostal vein
- Azygos vein
Vagus Nerve
- Right vagus nerve
- Left vagus nerve
Phrenic nerve
Thymus
Trachea
Where is the thymus located in a child?
Immediately beneath the sternum
NOTE: In the adult, the thymus usually undergoes involution to fat.
Within the superior mediastinum, the left brachiocephalic vein crosses and joins the right to form the ___________.
Superior vena cava
NOTE: The distal part of the superior vena cava is in the middle mediastinum
What are the branches of the arch of the aorta?
Brachiocephalic trunk
Left common carotid
Left subclavian
The _________ connects the aortic arch and left pulmonary artery.
Ligamentum arteriosum
What condition can be a sign of aortic aneurysm? Why?
Dysphonia
*This is becuase the left recurrent laryngeal neve passes posterior to the ligamentum arteriosum. Aortic aneurysm can cause compression onto the left recurrent laryngeal artery.
What is the course of the right laryngeal nerve?
Loops under the right subclavian artery then traveling upwards.
What is the course of the left recurrent laryngeal nerve?
loops under the aortic arch
Why do the left and right recurrent laryngeal nerves have different courses in the adult?
Because of the differntial development of the right and left 4th aortic arches
Are the bronchi in the mediastinum?
No because the trachea bifurcates at the sternal angle
Biopses of carinal nodes are done to test for what disease?
Lung cancer metastases
The esophagus is found directly posterior to which structure?
Trachea
The azygos vein terminates into the ______________.
Superior vena cava
Where does the azygos vein begin?
At the abdomen
Label
Label
Label
The anerior mediastinum is sandwhiched between the body of the __________ and the __________.
Sternum; pericardial sac
What are the contents of the anterior mediastinum?
Internal thoracic artery and vein
Transversus thoracis
The __________ forms the border of the middle mediastinum.
Pericardial sac
NOTE: The phrenic nerve is runing in the pericardial sac
The phrenic nerve provides __________ (sensory/motor) innervation to the pericardium.
Sensory
From which spinal nerves does the phrenic nerve originate? What is the clinical significance of this?
The phrenic nerve originates from spine nerves C3, C4, and C5 and because of this irritation of the pericardium produces referred pain in the shoulders.
What are the contents of the middle mediastinum?
Heart
Ascending aorta
Pulmonary trunk (proximal)
Superior vena cava (termination)
Label
An enlarged left atrium will displace the ____________.
Esophagus
Where is the posterior mediastinum found?
Between the pericardial sac and the vertebral column
What are the contents of the posterior mediastinum?
Descending aorta
Esophagus
Esophageal plexus (right and left CN X)
Thoracic duct
Azygos vein
Where does the descending aorta exit the thorax?
Through the aortic hiatus in the diaphragm at T12
What are the branches of the descending aorta?
Bronchial
Posterior intercostal
Esophegeal
The esophagus has 4 constrictions. What is the clinical signifance of this?
When passing instruments into the stomach, these four constrictions are potential sites where the esophagus may be perforated
What is the course of the esophagus?
- Begins in the neck at C6
- Cross the arch of the aorta
- Is crossed by the left bronchus
- Exits the thorax at esophageal hiatus in the diphragm at T10
What are the four esophageal constrictions?
- At the start of the esophagus, where the laryngopharynx joins the esophagus, behind the cricoid cartilage
- Where it is crossed on the front by the aortic arch in the superior mediastinum
- Where the esophagus is compressed by the left main bronchus in the posterior mediastinum
- The esophageal hiatus where it passes through the diaphragm in the posterior mediastinum