Mediastinum Flashcards
(35 cards)
What are the boundaries of the mediastinum?
superior: thoracic inlet and root of neck
inferior: diaphragm
anterior: sternum
posterior: vertebral column
What are the divisions of the mediastinum?
superior and inferior
what are the subdivisions of the inferior mediastinum?
middle: pericardium and heart
anterior: space between pericardium and sternum
posterior: space between pericardium and lower thoracic vertebrae
what are the boundaries of the superior mediastinum?
anterior: manubrium
posterior: first thoracic vertebrae
superior : root of the neck
inferior: is continuous with three compartments of inferior mediastinum
What are the contents of the superior mediastinum?6
the great vessels, trachea, esophagus, thoracic duct, vagus, phrenic nerves
What two veins joint to form the superior vena cava?
the right and left brachiocephalic vein
where is the right brachiocephalic vein formed?
at root of neck:
right subclavian and right internal jugular veing
where is left brachiocephalic vein formed
at root of neck
left subclavian and left internal jugular vein
what does superior vena cava contain?
venous flow from head, neck, both upper limpb
what is the anterior mediastinum?
space between pericardium and sternum
what are the boundaries and contents of middle mediastinum?
pericardium and heart
What are the boundaries and contents of posterior mediastinum?
space between pericardium and lower thoracic vertebrae
What is the aorta? What three branches is it divided into?
It is the main arterial trunk from the heart. It is divided into:
- Ascending aorta
- Arch of the aorta
- Descending aorta
Where does the ascending aorta lie? With what does it lie?
The ascending aorta lies in the fibrous pericardium. It is enclosed with the pulmonary trunk in a sheath of serous pericardium.
What are the three branches of the arch of the aorta? Where does each pass?
The three branches of the arch of the aorta are:
- Brachiocephalic artery – passes upward, to the RIGHT of the trachea, DIVIDES into the right subclavian artery and the right common carotid artery
- Left common carotid artery – runs upward, to the LEFT of the trachea and enters NECK
- Left subclavian artery – runs upward, along LEFT side of trachea and esophagus to enter NECK; arches over the APEX of LEFT LUNG
where does thoracic aorta begin and end
The thoracic aorta begins at the lower border of the fourth thoracic vertebra where it is continuous with the aortic arch, and ends in front of the lower border of the twelfth thoracic vertebra, at
What does the azygos venous system consist of?
It consists of
- The main azygos vein
- The hemiazygos vein
- Accessory hemiazygos
From where does the azygos system drain?
The azygos system drains from:
- The posterior parts of intercostal spa
- The posterior abdominal wall
- Pericardium
- Diaphragm
- Bronchi
- Esophagus
What is the origin of the azygos vein? What are its tributaries? How does it travel?
The azygos vein has a variable origin and numerous tributaries. It ascends through the aortic opening in the diaphragm on the right side of the aorta to the level of the 5th thoracic vertebra. It arches above the root of the right lung and empties into the posterior surface of the superior vena cava.
What is the origin of the hemiazygos vein? How does it travel?
The hemiazygos vein arises on the left side by the junction of the left subcostal and ascending lumbar veins; it ascends on the LEFT side of the vertebral column, POSTERIOR to the thoracic aorta to the level of T9, then crosses to the RIGHT to join the azygos vein.
What is the origin of the accessory hemiazygos vein? How does it travel?
The accessory hemiazygos vein descends on the LEFT side of the vertebral column, crossews over at the 7th thoracic vertebra to join the azygos vein; can join the hemiazygos vein.
What are the main nerves of the thorax? How do they travel?
The main nerves of the thorax are the:
- Right vagus nerve – descends in the thorax, passes behind the root of the right lung to form the pulmonary plexus, then onto the POSTERIOR surface of the esophagus to form the esophageal plexus, and descends through the esophageal opening of the diaphragm behind the esophagus to reach the POSTERIOR stomach.
- Left vagus nerve – descends in the thorax between the left common carotid and left subclavian arteries, crosses the left side of the aortic arch, turns behind the root of the left lung and forms the pulmonary plexus, then onto the ANTERIOR surface of the esophagus to form the esophageal plexus, and descends through the esophageal opening of the diaphragm in front of the esophagus to the ANTERIOR stomach
Which vagus nerve supplies the lungs and the esophagus?
Both vagi do
What does the right vagus give off? The left vagus?
The right vagus gives off cardiac branches.
The left vagus gives off the left recurrent laryngeal nerve
