Heart and mediastinum Flashcards
what are the boundaries of superior mediastinum
superior thoracic apeture to T4-T5
what are the contents of the superior mediastinum
- brachiocephalic vein
- arch of aorta
- thoracic duct (drains between internal jugular and subclavian)
- trachea
- oesophagus
- thymus
- vagus nerve
- L recurrent laryngeal
- phrenic
Compartments of inferior mediastinum
anterior, middle and posterior
boundaries of inferior mediastinum
transverse thoracic plane and diaphragm
contents of anterior mediastinum
thymus, lymph nodes and vessels, fat, connetive tissue, sternopericardial ligaments
contents and boundaries of middle mediastinum
boundaries: pericardial sac
heart, roots of great vessel, arch of azygous vein, main bronchi
contents of posterior mediastinum
oesphagus, thoracic aorta, azygous and hemi azygous, thoracic duct, vagus nerves, sympathetic trunks, splachnic nerve
boundaries of pericardial sac
2-6 costal cartilages, T5-T8
what does the pericardial sac consist of
fibrous: continuous with diaphragm - fuses with tunica adventitia of great vessels and attached to sternum via sternopericardial ligaments
stops heart overfilling
serous- 2 layers:
parietal-> lines fibrous
visceral-> lines heart = epicardium
what is the pericardial cavity
space in between parietal and visceral containing serous fluid to allow for frictionless movement
where is the transverse pericardial sinus
posterior to ascending aorta and pulmonary trunk
where is the oblique pericardial sinus
a wide recess posterior to heart formed by the serous pericardium which covers SVC, IVC and pulmonary veins
arterial supply of pericardium
pericardiocophrenic artery and internal thoracic artery branch
venous drainage of pericardium
pericardiocophrenic veins, brachiocephalic
azygous system
nerve supply of pericardium
phrenic nerves (sensory)
vagus nerve
sympathetic
layers of the heart
- epicardium (visceral pleura)
- myocardium- muscle
- endocardium- thin internal layer covering valves and heart
landmarks of apex of heart
posterior to left 5th ICS mid clavicular line
landmarks of base of heart
mainly LA, T6-T9
contents of anterior surface of heart
RV
contents of diaphragmatic surface of heart
LV, some RV
contents of L pulmonary surface of heart
LV
contents of R pulmonary surface of heart
RA
landmarks of border of heart
superior: 2nd LCC-> 3rd RCC
Right: 3rd cc to 6th cc
inferior 6th RCC to 5th L ICS mid clavicular
L: 5th ICS to 2nd CC
what does the RA consist of
- pectinate muscles in wall
- SVC opening: 3rd CC
- ICS opening 5th CC
- fossa ovalis: interatrial septum remnant of oval foramen
- right auricle: muscular pounch increases capacity of atrium and overlaps with ascending aorta
contents of RV
- trabeculae carnae: muscular ridges
- tricupsid valve: posterior to sternum 4-5th ICS
- tendinous chords: attach to valve cusps (anterior, posterior and septal)
- papillary muscles: attached to wall and chords
function of tendinous chords
prevent inversion and seperation of vlaves
function of papillary muscles
contract before RV contraction tightens tendinuous chords
where is the moderator band and what does it do
IV septum
part of R bundle branches to AV bundle to anterior papilary muscle
allows for coordinated contraction ‘shortcut’
landmark of pulmonary valve and number of cusps
3rd costal cartilage
3 semi lunar cusps
sinuses prevent valves sticking due to blood
contents of left atrium
- valveless R and L pul. veins
- L auricle: part of L border contains pectinate muscles
- smooth wall: absorption of parts of embryonic pulmonary veins
- rough wall: mainly auricle remains of L primordial atrium
contents of left ventricle
mitral valve- double leaflet with anterior and posterior cusps posterior to sternum at 4th CC
trabeculae carnae: finer and more numerous
anterior and posterior papillary muscles- larger
aortic sinuses
right drains into right coronary artery
left drains into left coronary artery
nothing arises from posterior
stenosis
failure of valve to open fully
valvular insufficiency
failure of valve to close completely- regurgiation
function of cardiac skeleton
- dense collagen- four fibrous rings
- keeps orifices, AV amd semilunar valves patent prevents over distention
- attachment for myocardium
- attachment for leaflet and cusps
- eletrical insulator- independent contraction of atria and ventricles
what does the right coronary artery supply
RA, SA (2/3), AV nodes 80%, 1/3 posterior part of IV septum
what does the left coronary artery supply
most of LA and LV, 2/3 anterior IV septum, AV bundles, may supply AV node 20%
where is the right recurrent laryngeal
crosses under and posterior to right subclavian artery. ascends lateral to trachea to the larynx
