Superior and Posterior Mediastinum Flashcards
What are the contents of the superior mediastinum from anterior to posterior?
Thymus Great vessels (veins then arteries) Vagus and phrenic nerves Left recurrent laryngeal nerve Cardiac pulmonary plexus Trachea Esophagus Thoracic duct Prevertebral muscles
The great vessels are the second most anterior structures in the superior mediastinum after the thymus. What great vessels exist in this compartment?
Brachiocephalic veins
Superior vena cava
Arch of the aorta with its 3 branches: brachiocephalic trunk, left common carotid a., left subclavian a.
Describe the location of the posterior mediastinum based on vertebral level and surrounding structures
Anterior to T5-T12, posterior to the pericardium, superior to the diaphragm, and medial to the pleural cavities
What are the contents of the posterior mediastinum?
Thoracic (descending) aorta Thoracic duct Lymph nodes Azygous and hemiazygous veins Esophagus Vagus nerve Esophageal plexus Thoracic sympathetic trunks Thoracic splanchnic nerves
What are the 4 major landmarks of the superior mediastinum?
Manubrium of sternum
Body of sternum
Blood vessels around manubrium
Thymus gland
The manubrium of the sternum is a superior mediastinal landmark. Which part of the manubrium corresponds to T2 vertebrae in men and T3 in women?
Suprasternal (jugular) notch
One of the landmarks for the superior mediastinum is the body of the sternum. The sternal angle connects to the second costal cartilage laterally. What is this a landmark for?
Bifurcation of the trachea and beginning of the aortic arch
What blood vessels can be found using the manubrium of the sternum as a landmark in the superior mediastinum?
Arch of the aorta
Right and left brachiocephalic veins
Brachiocephalic trunk, right subclavian vessels, common carotids
What superior mediastinal landmark is found behind the manubrium and body of the sternum?
Thymus gland
The cardiac and pulmonary plexus include the ______ nerves which run anterior to the roots of the lungs.
The ______ nerves run posterior to the root of the lung and give off the ________ nerve which hooks around the ligamentum arteriosum.
Phrenic
Vagus; left recurrent laryngeal
At what spinal cord levels would you find the sympathetic preganglionic cells of the cardiac and pulmonary plexus? Where are the postganglionics?
T1-T4/5; postganglionics in sympathetic chain
T/F: parasympathetic preganglionic fibers of the cardiac and pulmonary plexus are from the phrenic nerve
False; from the vagus nerve
Where would you find postganglionic parasympathetic fibers of the cardiac and pulmonary plexus?
Heart: Ganglia in epicardium/inner aortic arch
Lungs: small ganglia along bronchiolar tree
The usual pattern of branches of the aortic arch is present in 65% of people. What is the usual pattern?
Brachiocephalic trunk
Left common carotid a.
Left subclavian a.
Variations in the origin of the branches of the aortic arch are fairly common. In 27% of people, the left common carotid artery originates from the __________
Brachiocephalic trunk
Variations in the origin of the branches of the aortic arch are fairly common. A brachiocephalic trunk fails to form in approximately 2.5% of people. What happens in this case?
Each of the 4 arteries (right and left common carotid and subclavian arteries) originate independently from the arch of the aorta
Variations in the origin of the branches of the aortic arch are fairly common. In addition to the normal pattern, the _______ artery originates from the arch of the aorta in 5% of people
Left vertebral
T/F: both right and left brachiocephalic trunks originate from the aortic arch in approximately 1.2% of people
True
A __________________________ artery sometimes arises as the last (most left-sided) branch of the arch of the aorta. This artery crosses posterior to the esophagus to reach the right upper limb and may compress the esophagus, causing dysphagia
Retro-esophageal right subclavian
Variations in the origin of the branches of the aortic arch are fairly common. An accessory artery to the thyroid gland, the _________ artery, may arise from the arch of the aorta or the brachiocephalic artery
Thyroid ima
What are some anomalies that may occur with the aortic arch itself?
Right arch of the aorta (curves over root of right lung and passes inferiorly on right side)
Double arch of the aorta (forms vascular ring around esophagus and trachea, may cause compression)
What aortic branches are present in the posterior mediastinum?
Superior phrenic aa. Posterior intercostal aa. Esophageal aa. Bronchial aa. Tracheal aa. Supreme intercostal aa.