Mesiastinum Flashcards
Major parts of the thoracic cavity
- 2 pulmonary cavities where the lungs occupy
- The mediastinum: the central compartment
Major subdivisions of the mediastinum
- Superior Mediastinum
- Inferior Mediastinum
- Anterior Mediastinum
- Middle Mediastinum
- Posterior Mediastinum
Boundaries of the superior mediastinum
(superior to inferior)
-Extends from an oblique plane thorugh the jugular notch and T1 vertebra to a horizontal plane through sternal angle and T4/5 intervertebral disc
Boundaries of the inferior mediastinum
(Superior to inferior)
-Extends from the sternal angle and T4/5 intervertebral disc to the diaphragm.
Parts of the superior mediastinum (selected contents for this course)
- Thymus
- “Great” vessels
- Vagus and phrenic nerves
- Trachea
- Esophagus
- Thoracic duct
Thymus(location and function)
-At the root of the neck, superior and anterior mediastinum
-Most anterior structure in the superior mediastinum
immediately deep to the manubrium
-Primary lymphoid organ
“Great” arteries(list)
- Arch of the aorta
- Brachiocephalic trunk
- Left common carotid artery
- Left subclavian artery
“Great” Veins(list)
- R & L brachiocephalic veins(BCV)
- Superior vena cava(SVC)
Arch of the Aorta(Connections and location)
- Begins at the level of sternal angle, posterior to the 2nd right costosternal joint.
- Ascends anterior to the right pulmonary artery and trachea.
- It is the continuation of the ascending aorta then continues into the descending thoracic aorta
List the aortic arch branches in order
- Brachiocephalic trunk
- Left common carotid artery
- Left subclavian artery
Branches of the Brachiocephalic trunk
- Right subclavian artery
- Right common carotid artery
What veins drain into the brachiocephalic veins(BCV) and where does it occur?
The internal jugular and subclavian veins.
posterior to the sternoclavicular joints
Where do the BCVs join and where?
- The right and left BCVs join into the superior vena cava
- At the level of the 1st right costal cartilage
Superior vena cava(Location)
Forms at the 1st costal cartilage, passes through the middle of the mediastinum and terminates at the level of the 3rd costal cartilage
Left vagus nerve(Location)
-Enters into the superior mediastinum posterior to the L brachiocephalic vein, then anterior to the aortic arch and posterior to the root of the lung (in the posterior mediastinum now)
Branches of Left vagus nerve and where it branches
- some branches contribute to the pulmonary plexus.
- some pass inferiorly contribute to the esophageal plexus and anterior vagal trunk
- The left recurrent laryngeal nerve branches off at the aortic arch and ascends between the trachea and esophagus
Right vagus nerve (location)
-Enters into the superior mediastinum posterior to the brachiocephalic vein, then posterior to the superior vena cava and along the right margin of the trachea then posterior to the root of the lung
Branches of right vagus nerve and where it branches
some branches contribute to the pulmonary plexus other pass inferiorly to the esophageal plexus and posterior vagal trunk
-The right recurrent laryngeal nerve does NOT branch off in the mediastinum
Phrenic nerve(motor supply, sensory supply)
- the only motor supply is to the diaphragm
- sensory branches to the pericardium, mediastinal pleura and diaphragm
Phrenic nerve (location ) and what runs with it?
- Pass anterior to the subclavian artery and posterior to he subclavian vein. then enters the superior mediastinum.
- Pericardiacophrenic vessels travel wit the phrenic nerves. All 3 pass anterior to the root of the lung the descend into the middle mediastinum between the fibrous pericardium and the mediastinal pleura
Where do the trachea and esophagus start?
at C6
Trachea(location)
courses anterior to the esophagus and ends at sternal angle (does not enter the inferior mediastinum)
Esophagus(location)
Passes from the superior to the posterior inferior mediastinum to reach the diaphragm at T10 and ends at T11
Function of the thoracic duct
Conveys most lymph of the body to the venous system except the upper right quadrant (which includes the right side of the neck, head, thoracic wall/cavity and UE)
