Mediastinum
What divides the mediastinum into superior and inferior components and what level does it lie
Transverse thoracic plane, it passes through the sternal angle anteriorally and the intervertebral disc between T4 and T5 posteriorly
The inferior mediastinum is divided into what
Anterior middle and posterior compartments
What does the thoracic duct contain
Lymph
Where does the azygos vein pass through the diaphragm and empty
T12 and superior vena cava
What is the mediastinum
central area of the thorax that lies
between the two pleural cavities.
What structure separates the middle mediastinum from the other compartments
Fibrous pericardium
Where does the thoracic duct empty
Venous system at the left venous angle
Which structures are drained by the azygos system of veins?
Posterior thoracic wall, bronchi, pericardium & oesophagus
State the boundaries of the superior, inferior, anterior and posterior mediastina
Superior boundary - superior thoracic aperture
Inferior boundary - diaphragm
Anterior boundary - sternum
Posterior boundary – thoracic vertebrae
State the anterior and posterior boundaries of the anterior mediastinum
Anterior – sternum
Posterior – fibrous pericardium
State the anterior and posterior boundaries of the posterior mediastinum
Anterior – upper surface of diaphragm & fibrous
pericardium
Posterior - thoracic vertebrae 5-12
Which vessels drain into the azygous vein
Lower 8 right posterior intercostal veins, superior intercostal vein, hemiazygos & accessory hemiazygos veins
State the contents of the superior mediastinum (from anterior to posterior)
Thymus
Brachiocephalic veins & SVC, arch of aorta & branches (brachiocephalic trunk, left common carotid & subclavian), vagus and phrenic nerves, cardiac plexus
Trachea
Oesophagus
Thoracic duct & lymphatic trunks
State the contents of the anterior mediastinum
sternopericardial ligament, fat, remnants of thymus
List the contents of the posterior mediastinum
Oesophagus, thoracic aorta, azygos system of veins, thoracic duct, sympathetic chains, vagus nerves
A widened mediastinum seen on a chest X-ray following trauma may indicate rupture of this major blood vessel.
Aorta
State the superior and inferior boundaries of the inferior mediastinum
Superior - transverse thoracic plane Inferior - diaphragm
List the contents of the middle mediastinum
Pericardium
Heart
Roots of great vessels (SVC, ascending aorta, pulmonary trunk, pulmonary veins)
Lung roots
Phrenic nerves
Cardiac plexus
Where does the thoracic duct begin
At the cysterna chyli (level LV1 & LV2)
Compression of this structure in the superior mediastinum can cause hoarseness due to its role in innervating the vocal cords.
Left recurrent laryngeal nerve