5. The Thoracic Mediastina Flashcards
What are the borders of the superior and inferior mediastina?
superior border of the superior mediastina = rib 1
superior border of the inferior mediastina = sternal angle (t4/t5 manubriosternal joint)
inferior border of the inferior mediastina = diaphragm
What is the middle part of the inferior mediastinum bound by?
fibrous pericardium
What structure(s) can be found in the anterior mediastinum?
- Thymus gland: immune organ that produces t cells
- in adults it atrophies and become smaller bc no longer needed to develop immune system as in a child - lymph nodes
- fat and connective tissue
What structure(s) can be found in the superior mediastinum? 8
- svc -> r/l brachiocephalic v -> r/g jugular v + r/f subclavian v
- arch of aorta
a) brachiocephalic trunk: right subclavian a + right common carotid a
b) left common carotid a
c) left subclavian a - thoracic duct
- trachea
- esophagus
- r/g vagus nerve and their recurrent laryngeal n
- l/r sympathetic trunk
- phrenic n
Where do each recurrent laryngeal nerve travel?
right: wraps around subclaian a or brachiocephalic trunk
left: returns back up to larynx after wrapping around aorta and inn inferior part of the larynx (internal vocal folds)
How can you tell the difference between the vagus nerve and the phrenic nerve in the lab?
vagus nerve has its recurrent laryngeal n
phrenic goes to diaphragm
phrenic travels in front of the hilum
vagus travels posterior to the hilum
Where do you find the left pericardiacophrenic artery?
its a branch off of the internal thoracic a that runs w the phrenic n and is bound to the fibrous pericardium (goes to heart and diaphragm)
What occurs if there is ______ damage to the vagus nerve?
a) unilateral
b) bilateral
dead in both cases
What occurs if there is ______ damage to the recurrent laryngeal n?
a) unilateral
b) bilateral
a) hoarseness (damage to vocal folds)
b) respiratory issues
What is the superior laryngeal n? why does the recurrent laryngeal n. travel down only to travel back up?
superior laryngeal n: goes directly to inn the larynx
recurrent: due to embryology: the aorta would pull down the reccurent
What is can be found in the middle mediastinum? 7
- the heart with its coronary arteries and cardiac veins and cardiac plexus
- ascending aorta
- the entire pulmonary trunk
- SVC and IVC
- primary bronchi
- Right and left phrenic n that runs with the right and left pericardiacophrenic a (both adhere to the fibrous pericardium)
- pulmonary arteries and veins
What can be found in the posterior mediastinum? 6
(past heart and trachea)
- descending aorta (thoracic aorta) (deep to esophagus)
- gives off the posterior intercostal arteries + esophageal branches - esophagus: and its esophageal plexus (combination of sympathetic trunk and parasympathetic n)
- Azygous Vein: and its posterior intercostal veins (right side) and hemizygous veins (left side)
- sympathetic trunk: with its rami communicans
- thoracic duct
- posterior and anterior vagal nerves
TRICK: birds of the thoracic cage: vagoose, esophagoose, thoracic duck, azygoose and hemizygoose
Describe the 3 hiatuses of the diaphragm.
- the caval hiatus: for the inferior vena cava @T8
- the esophageal hiatus @T10
- the aortic hiatus @T12
What do the left and right vagus nerve give off that enter the esophageal hiatus?
left vagus nerve gives off the ANTERIOR vagal trunk (because left is more posterior)
right vagus nerve gives off the POSTERIOR vagal trunk (because right is more anterior)
Explain the positioning of the contents of the posterior mediastinum in relation to the verterbral bodies.
abdominal aorta +azygous v+ thoracic duct = bundle
posterior to this bundle = esophagus
left and right vagal trunks travel with the esophagus through the esophageal hiatus
Describe the differences between the right and left view of the thoracic cage.
LEFT:
- vagus n goes behind the hilum
- recurrent laryngeal loops around arch of aorta
- hemizygous v
- aorta
- ligamentum arteriosus
RIGHT:
- IVC
- azygous v
