Mediastinum Flashcards
What is the mediastinum?
Thick midline partition spearating the 2 pleural cavities
How far does the mediastinum extend?
From superior thoracic aperture to inferior thoracic aperture and between sternum ant and thoracic vertebrae post
What is the mediastinum for?
Acts as a conduit for structures that pass from one body region to the other and for tructures that connect thoracic organs to other body regions
What are the main contents of the mediastinum?
Trachea (larynx to bifurcation into principal bronchi), oesophagus (pharynx thru diaphragm at T10), heart, pericardium, thoracic duct, nerves, great vessels
How is the mediastinum divided?
Superior (above sternal angle), Inferior (below sternal angle), Anterior (to heart), Middle (heart), Posterior (to heart and diaphragm)
What are the contents of the superior mediastinum from anterior to posterior?
Thymus, Phrenic Nerves, Braciocephalic veins, thoracic duct, Vagus nerves, great arteries, Trachea and main bronchi, Upper oesophagus, left recurrent laryngeal nerve
At what level does the trachea end?
T4-5 where the 2nd costal cartilage attaches - Sternal angle
What are the great arteries present in the mediastinum?
(off the aortic arch)
brachiocephalic trunk (splits into right subclavian and common carotid), Left common carotid, left subclavian and right
What are the great veins?
SVC (enters right atrium from above) and IVC (enters right atrium from below through central tendon of the diaphragm)
Where is the phrenic nerve embedded?
In the pericardial sac
At what level is the aortic arch?
The top is at the sternal angle
What does each brachiocephalic vein branch off into?
Internal jugular (from head) and subclavian( from upper limbs) vein
How do the brachiocephalic veins (BCV) join to become the svc?
Left BCV crosses from left to right, posterior to the manubrium, joining the R BCV
Where does each brachiocephalic vein branch sit?
Underneath each sternoclavicular joint
In which part of the mediastinum are the arch, ascending and descending aorta?
Arch: superior, Ascending: middle and descending: posterior Asc and Desc are both in the inferior mediastinum
What are the first branches of the ascending aorta?
Right and left coronary arteries
What branches from the aortic arch?
Brachiocephalic trunk, left common carotid and left subclavian
How does the aorta relate to the airways?
Arch rises anterior to trachea and over the left main bronchus at the lung root