Anatomy of the Mediastinum Flashcards
From an anterior view, the esophagus is…
a) anterior to the trachea
b) posterior to the trachea
b) posterior to the trachea
The 3 branches of the aortic arch are..
- Brachiocephalic trunk
- Left common carotid
- Left subclavian artery
The branchiocephalic trunk branches out into… (2)
- Right common carotid
- Right subclavian
The superior vena cava branches out into… (2)
- Left brachiocephalic vein
- Right brachiocephalic vein
The brachiocephalic veins further branch out into… (2)
Internal jugular veins and subclavian veins
Where can you find the arch of the azygous vein?
In the superior mediastinum, drains into SVC.
What important lymphatic structure is located in the superior mediastinum?
Thoracic duct (on the left side)
What is the function of the thoracic duct? Where does it drain?
Returns 75% of total lymphatic fluid to venous circulation. It drains at the venous angle between the left subclavian and the left internal jugular veins.
What is the main nerve found in the superior mediastinum?
Vagus nerve (running down both on the left and right).
Which laryngeal nerve has a longer course? What do they branch off of?
The left laryngeal nerve is longer than the right. Both branch off the vagus nerve (L&R).
Which laryngeal nerve passes through the superior mediastinum, and which does not?
Left laryngeal nerve has a portion in the superior mediastinum, the ight does not.
The vagus nerve is also known as…
the cranial nerve X
In the superior mediastinum, the vagus nerve gives rise to…
parasympathetic nerves that contribute to the cardiac and pulmonary plexuses.
What do laryngeal nerves innervate?
Laryngeal nerves innervate most laryngeal muscles (muscle of the larynx).
Impingement of laryngeal nerves can lead to…
hoarseness or dysphonia.
The left laryngeal nerve branches off the vagus and loops under…
The right laryngeal nerve branches off the vagus and loops under…
The left laryngeal nerve branches off the vagus and loops under the AORTIC ARCH.
The right laryngeal nerve branches off the vagus nerve and loops under the BRACHIOCEPHALIC TRUNK or RIGHT SUBCLAVIAN.
The anterior mediastinum is primarily occupied by…
the thymus gland
What is the function of the thymus gland?
Organ of the lymphatic system, responsible for the differentiation of T cells.
How does the thymus gland change with age?
Because it is involved with immune system development, it will be larger in childhood/youth and will degenerate in adults (becomes fibro-fatty tissue).
What are the 5 important components of the middle mediastinum?
- Heart
- Neurovasculature outside the pericardium (phrenic nerve, pericardiacophrenic arteries and veins)
- Neurovasculature inside the pericardium (cardiac plexus, coronary circulation)
- Roots of great vessels
- Primary bronchi
How come the posterior mediastinum communicates freely with the superior mediastinum?
Because many structures are continuous between these two compartments, e.g. sympathetic chain, vagus nerve, esophagus, aorta, azygos vein, thoracic duct).
Which part of the mediastinum houses the descending aorta?
Posterior mediastinum
Azygos and hemi-azygos veins drain…
the posterior thoracic and abdominal walls
The azygos vein provides a collateral passage for venous blood to…
bypass blockages in the vena cavae
The thoracic duct drains 3/4 of the body’s lymph. What drains the remaining 1/4?
The right lymphatic duct (into the brachiocephalic veins and at the venous angles)
The thoracic portion of the aorta gives rise to…
the posterior intercostal arteries from rib 3 to 12
Posterior intercostal arteries anastomose with
anterior intercostal arteries
Posterior intercostal arteries are found between what muscle layers?
Internal and innermost intercostal muscles
The esophagus passes through the diaphragm at the level…
T10
The esophagus is a muscular tube that connects the … to…
connects the pharynx to the stomach
Which subdivisions of the mediastinum does the esophagus run through?
The superior and posterior mediastinum
How is the esophagus positioned relative to the aorta in the posterior meidastinum?
At first, it is to the right of the aorta, but then moves anterior to the aorta and through the diaphragm.
The opening in the diaphragm for the esophagus is called…
esophageal hiatus
As they enter the posterior mediastinum, the vagus nerves pass…
a) anterior to the hilum of the lungs
b) posterior to the hilum of the lungs
b) posterior to the hilum of the lungs
Below the hilum of the lungs:
The right vagus nerve becomes…
The let vagus nerve becomes…
The right vagus nerve becomes the posterior vagal trunk.
The left vagus nerve becomes anterior vagal trunk.
LARP mnemonic
