mediastinum Flashcards
how is the mediastinum divided up?
superior and inferior (to an imaginary line through the sternal angle)
Inferior divided into anterior, middle and posterior
what are the borders of the superior mediastinum?
superior - superior thoracic aperture lateral - pleura of the lungs anterior - sternum posterior - vertebral bodies T1-T4 inferior - continuous with inferior mediastinum
What is in the superior mediastinum?
SVC, left and right brachiocephalic veins Pulmonary artery aorta, brachiocephalic trunk, left common carotid and left subclavian trachea oesophagus thoracic duct vagus and phrenic nerve infrahyoid muscles sympathetic trunk
what are the borders of the middle mediastinum?
Anterior: Anterior margin of the pericardium.
Posterior: Posterior border of the pericardium.
Laterally: Mediastinal pleura of the lungs.
Superiorly: Imaginary line extending between the sternal angle (the angle formed by the junction of the sternal body and manubrium) and the T4 vertebrae.
Inferiorly: Superior surface of the diaphragm.
what are the contents of the middle mediastinum?
heart ascendign aorta SVC Pulmonary trunk phrenic nerve cardiac plexus hilar lymph nodes
what nerves contribute to the cardiac plexus?
vagus nerve - parasympathetics
T1-T4 spinal cord - sympathetics
what are the borders of the posterior mediastinum?
Lateral: Mediastinal pleura (part of the parietal pleural membrane).
Anterior: Pericardium.
Posterior: T5-T12 vertebrae.
Roof: Imaginary line extending between the sternal angle (the angle formed by the junction of the sternal body and manubrium) and the T4 vertebrae.
Floor: Diaphragm.
what are the contents of the posterior mediastinum?
oesophagus thoracic duct thoracic aorta IVC sympathetic trunk azygous system
what are the borders of the anterior mediastinum?
Lateral borders: Mediastinal pleura (part of the parietal pleural membrane).
Anterior border: Body of the sternum and the transversus thoracis muscles.
Posterior border: Pericardium.
Roof: Continuous with the superior mediastinum at the level of the sternal angle.
Floor: Diaphragm.
what are the contents of the anterior mediastinum?
sternopericardial ligaments and thymus (in children)
where is the fibrous pericardium attached to?
diaphragm
sternum
tunica adventitia of great vessels
what is the transverse pericardial sinus?
between arteries and veins entering/leaving the superior heart
anterior: pulmonary artery and aorta
posterior: SVC
what are the layers of the pericardium?
fibrous
parietal and visceral pericardium known as serous pericardium
what are aortic sinuses are where are they?
where the coronary arteries branch from the aorta
just distal to aortic valve behind the valve leaflets - when the heart enters diastole and the aortic valve closes, the backflow of blood into the leaflets is sucked into the coronary arteries as the pressure is lower in them during diastole
describe the path of the left coronary artery
branches from the left of the aorta and travels posterior to the pulmonary trunk, emerging in the left coronary sulcus
what are the branches of the LCA
LAD
Left marginal
left circumflex
may contribute to PIV artery if left dominant
what are the branches of the RCA
Right marginal, PIV artery
describe the path of the right coronary artery
travels in the right coronary sulcus inferiorly between the right atria and rigth ventricle on the anterior surface of the heart before giving off its marginal branch which travels medially along the inferior surface of the right ventricle.
the RCA then travels posteriorly to usually give off the posterior interventricular artery which descends in the posterior interventricular groove
where do diagonal coronary artery branches branch from?
LAD - descend diagonally over the left ventricle
what does the LAD supply?
what does the LCx supply?
what does the left marginal supply?
what does the right coronary artery supply
what does the right marginal artery supply?
what does the posterior interventricular artery supply?
where does the venous drainage of the heart drain into?
coronary sinus in right atrium
where does the coronary sinus run?
continuation of great cardiac vein - runs along inferior border of left atrium towards right atrium