Org Ana: Mediastinum and Heart Flashcards
what is the mediastinum
tough and thick movable partition betw sternum and pleural cavities and the vertebrae
divides into superior and inferior through the plane passing sternal angle anteriorly and lower border of T4 body
what are the boundaries of the mediastinum
sup - thoracic outlet and root of neck
inf - diaphragm
ant - sternum
post - thoracic vertebrae
lat - pleura
describe the superior mediastinum
above the sternal angle
boundaries:
ant - manubrium
post - T1-T4
what are the contents of superior mediastinum
thymus gland
large veins
large arteries
trachea
esophagus and thoracic duct
describe the inferior mediastinum
below the sternal angle and divides into anterior, middle and posterior
boundary:
ant - body of sternum
post - T5-T12
what are the contents of inferior mediastinum
ant: thymus
middle: heart with pericardium and phrenic nerve on sides
post: esophagus and thoracic duct, descending aorta and sympathetic trunks
what is the pericardium
fibroserous sac enclosing heart and roots of great vessels
lubricated container and prevent excessive movement
boundaries:
ant - body of sternum
lat - 2nd to 6th CC
post - T5-T8
describe serous pericardium
lines fibrous pericardium and coats heart
parietal - inner of fibrous pericardium and reflex around roots of great vessels
visceral - applied to epicardium
parietal continues to become visceral
what is the pericardial cavity
space between parietal and visceral that contains 50 ml of pericardial fluid
describe fibrous epicardium
strong fibrous outer layer attached to central tendon
fuses w outer coats of great vessels
attaches to sternum via sternopericardial ligament
what is pericarditis
inflammation of pericardium bc of excessive fluid that causes compression of the atrium interfering with filling during diastole
what is cardiac tamponade
can occur secondary to stab or gsw when chambers are penetrated
compression of heart
describe the heart
muscular organ
pyramidal
found in mediastinum
connected at the base to great vessels
describe the orientation of the heart
oblique w apex pointing down, forward and left
2/3 midline on left side
LV from apex at 5th ICS 3.5 in away from midline
what is the sternocostal surface of the heart
anterior surface formed by RA and RV separated by AV groove or coronary sulcus
anterior interventricular groove separates RV and LV
what is the diaphragmatic surface of the heart
inferior surface formed by RV and LV separated by posterior interventricular groove
inferior surface of atrium where IVC opens forms part of this
what is the base surface of the heart
posterior surface formed by LA where 4 pulmonary veins open
opposite apex
what are the borders of the heart
right - RA
left - left auricle and LV
inferior - RV and portion of RA
apex - LV
discuss the layers of the heart from superficial to deep
epicardium - visceral pleura
myocardium - cardiac muscle; contracts
endocardium - endothelium on CT; lines heart and creates valves