Mediastinum Flashcards
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Why do diaphragm have flat muscles unlike othere
Cause inferior vena cava, aorta and oesophagus pass through. If muscles are solid and they contract, could cause constriction of those vessels
Boundaries of mediastinum
Superior thoracic inlet Sternum and costal cartilage Diaphragm Thoracic vertebral columns *Laterally by mediastinal pleura
Contents of superior mediastinum
Arch of aorta Brachiocephalic trunk roots Oesophagus Trachea Thymus Brachiocephalic vein Superior vena cava Phrenic nerve Vagus Thoracic duct and right lymphatic duct
Boundaries of anterior mediastinum
Posterior boundary is pericardium
Anterior boundary is body of sternum
Can add trans thoracic plane and diaphragm I suppose
Contents of anterior mediastinum
Loose connective tissue and fat
Thymus
Lymph nodes
Contents of middle mediastinum
Mostly pericardium Ascending aorta, superior vena cava, pulmonary trunk Phrenic nerve laterally Lymph nodes Tracheal bifurcation and main bronchi
Mediastinal pleura and pericardium are supplied by
Phrenic nerve
Posterior mediastinum boundaries?
Anteriorly by bifurcation of trachea, pulmonary vessels, pericardium and upper surface of diaphragm
Posteriorly by t5 to t12 vertebrae
Laterally by mediastinal pleura
Contents of the posterior mediastinum?
Descending thoracic aorta
Azygos, hemizygos and accessory azygos veins
Right and left sympathetic chains, splanchnic nerves(branches of sympathetic chain) and left and right vagi nerves
Oesophagus
Thoracic duct
Posterior mediastinal lymph nodes
Descending thoracic aorta lies in which side of thoracic vertebrae and inferior vena cava lies on which side?
Left and right
Which part of diaphragm does inferior vena cava pass and why?
Pass through central tendon and not muscle bc, blood flows through veins slowly so if it is placed in muscle and it contracts it will prevent backflow of blood and venous return, which will in turn affect cardiac output
Length of trachea, diameter, begins, ends?
10cm, 2cm, C6 vertebra, lower border of cricoid cartilage level and ends at the T5 or sternal angle.
Relations. Oesophagus posteriorly, aortic arch anteriorly
Which arteries supply the trachea
Bronchial artery, inferior thyroid artery
Nerve supply to the arteries?
Vagus supply mucosa, sympathetic chain supply smooth muscle structure
Thoracid duct receives lymph from the while body except
Right upper limb and right side of the head and the nexk
Where does the thoracic duct empty
Junction between left internal jugular vein and left subclavian vein
Where do sympathetic and parasympathetic supply of heart come from
Sympathetic supply from sympathetic chain
Parasympathetic supply from vagus nerve
Vagus?
Cranial nerve X
Major parasympathetic supply to thoracic and abdominal viscera
Course of vagus nerve
Runs parallel to oesophagus and innervate
Passes posterior to root of lung on each side
Pierces diaphragm with oesophagus
Course of 9hrenic nerve
Arises from central rami of C3-C5. C4 majorly
Passes anterior pulmonary root on each side. Only nerve to do that
Phrenic nerve supplies?
Pericardium, mediastinal pleura, pleura and peritoneal coverings of diaphragm
What are mediastinal shifts?
Shifting of organs and tissues of mediastinum to one side of the chest
Note that increased volume of air causes mediastinum to shift to opposite side
Fibrosis or tumour makes lung heavier and pushes mediastinum towards ir
Haemothorax
Haemothoraxrefers to a collection of blood within the pleural cavity.
Cardiac tamponade?
Accumulation of fluid in the pericardiuma round the heart causing it to work harder and enlarge as a result
Pneumothorax?
A collapsed lung.
This condition occurs when air leaks into the space between the lungs and chest wall.
Pleural effusion?
A build-up of fluid between the tissues that line the lungs and the chest.
Fluid can accumulate around the lungs due to poor pumping by the heart or by inflammation
Pyothorax?
Pyothoraxrefers to the presence of inflammatory fluid or pus within the chest cavity, which is the area between the lungs and the inner walls of the ribs.
Phrenic nerve accompanied by
Pericardiacophrenic arteries
