Middle Mediastinum: I Flashcards
(18 cards)
Where is the middle mediastinum located & what are its contents?
- Centrally located
- between plural cavities
- Contains
- pericardium
- fibrocollagenous sac
- heart
- major bessel roots
- SVC & IVC
- pulmonary trunk
- aorta coronary vessels
- pericardium
What are the 3 important layers of the pericardium?
Innervation?
- Layers
- fibrous pericardium
- outer DCT
- Serous pericardium
- parietal layer (line interior of fibrous)
- visceral layer (coat the heart)
- pericardial cavity
- fibrous pericardium
- Blood Supply
- pericardiacophrenic artery
- from internal thoracic
- pericardiacophrenic artery
- Innervation
- phrenic
- dermatomes C3-5
- can refer pain to the top of the shoulder
- phrenic
Identify the layers overlying the heart
What is Pericardial Effusion?
What can it reslut in?
Treatment?
- Pericardial effusion
- in pericardial cavity
- inflammatory process (can get puss)
- Results in (fibrous pericardium doesn’t stretch well in an acute setting)
- compression of heart
- cardiac tamponade
- biventricular failure (decrease its capacity to move blood)
- compression of heart
- Treatment
- needle aspiration of fluid - or can go into heart failure
- pericardiocentesis
- 5th-6th intercostal space
- paraxyphoid / costal margin
- pericardiocentesis
- needle aspiration of fluid - or can go into heart failure
What are the names of the gaps in the pericardium?
- oblique pericardial sinus
- gap behind the heart between heart & pericardium
- backwards J / or L shape around & inbetween the pulmonary & caval veins
- transverse pericardial sinus
- behind pulmonary trunk & behind aorta
- btw aa. & vv.
- can pass tools behind this area to clamp off those great vessels to do a procedure
Identify the surfaces of the heart indicated by the colors
yellow
pink
blue
green
purple
red
- Sternocostal (anterior)
- abuts sternum & ribs
- main made up of right ventricle
- Diaphragmatic (inferior)
- sits on the diaphragm
- mainly right ventricle
- Posterior (base)
- left atrium
- Left & right pulmonary
- abuting pleura/mediastinum portion of the lungs
- Apex
- left 5th intecostal space
- 7-9 cm from midline
- auscultation of mitral valve
Identify the indicated features of the heart
Identify the margins indicated by the arrows
- Acute (inferior margin) - red
- right ventricle (ant./post.)
- btw anteiror surface & diaphragmatic surface
- Obtuse margin - blue
- left ventricle
- Left margin - green
- left ventricle & auricle
- Right margin - purple
- right pulmonary surface
- right atrium
- right pulmonary surface
Identify the sulci outlined in green and blue in the provided image
- Coronary
- separates
- artia and ventricles
- atrioventricular AV sulcus
- separates
- Interventricular
- anterior and posterior
- separate
- left and right ventricles
How can you differentiate between the left and right ventricles?
left ventricle has thicker walls
blood from the pulmonary vein is delivered direcly to what 5 structures?
- left atrium
Describe the circulation of blood in the body with relation to where blood is received from & sent to from the 4 cambers of the heart
- Right atrium
- blood from
- SVC & ICV
- coronary sinus
- blood from
- Right ventricle
- blood from right atrium
- blood to pulmonary trunk
- Left atrium
- blood from pulmonary veins
- Left ventricle
- blood from left atrium
- blood to the aorta
What are the two sections of the right atria? Openings & important characteristics?
Identify the inidcated features on the provided image
-
Sinus vina cavae
- smooth area of right atrium in alignment with the superior & inferior vena cava
- opening to inferior vena cava has a valve
- also opening & valve for the coronary sinus
- coronary blood flow that comes back
-
Fossae ovalis
- on septal wall have oval shaped depression
- limbus = ridge
- separated from rough area via crista terminalis
- smooth area of right atrium in alignment with the superior & inferior vena cava
-
Pectinate muscle (muscle of the proper atrium)
- terminates via the crista terminalis
- at posterior aspect of the auricle & adjacent to superior vena cava
- SA node is found between the crista terminalis & the superior vena cava
- auricle = ear-like appendace at the top of the atrium
- Tricuspid valve between right atrium & right ventricle
- terminates via the crista terminalis
What are the two sections of the right ventricle? Openings & important characteristics?
Identify the inidcated features on the provided image
-
Trabeculae carnae
- musculature of ventricle
- inflow area
-
septomarginal trabecula
- between septal wall & inferior margion of the heart
-
papillary muscle
- trabeculae carnae that come off the wall & attach to the valve
- anterior, posterior & septal based on the tricusped leaf they attach to
- chordae tendineae are the tendons attaching the muscles to the cusps of the valve
-
Conus arteriosus
- smooth wall (outflow area) toward pulmonary tract
- pulmonary semilunar valve at base of the pulmonary trunk
- does not have chords nor muscles, just flaps of tissues
- formed by 3 cusps
Identify the indicated valves of the heart
Which image shows sytole & which shows diastole?
- Each valve has a cartilagenous ring around the base of the valve that are anchored together
- so they are roughly found in a the same plane betweent he chambers of thee heart//associated large vessel
- Top left image is during diastole
- heart is relaxed
- orfice between atria & ventricles are open
- pulmonary & arotic valves are closed
- Bottom right image is during systole
- ventricles are contracting, causign atrioventricular valve to close
- papillary muscles will contract when valve is closed, pullingon the chords, keeping the cusps from reverting up into the atria
- output of right ventricle is pulmonary trunk
- output of left ventricle is aorta
Describe how the valves between the ventricles & trunks work and identify the inidicated components in the provided image
- Components of cusps
- Lunule: sharp edge
- Nodule: thickening along lunule where you will see the 3 valves come together
- Siunus: pocket behind
- Working
- if blood pushes up through it will cause the cusp to flatten against the wall
- when pressure is greater in the trunk, trying to regurgitate back toward the ventricle, its going to fill up the cusps w/ blood and as the cusps come together at the center point sealing it off
Identify the indicated features of the left atrium & note any unique characteristics of the left atrium
- Four pulmonary veins
- intra-atrial septum
- right atrium on other side of wall
- auricle
- location of pectinate muscle
- not quite as much as the right atrium
What percent of blood that go through the atria enter passively through the ventricles?
Why is this clinically important information?
75-80%
The pectinate muscles of the atria are only responsible for pushign 20-35% of the blood through, so atrial fibrillation is much less damaging to the situation than ventricular fibrillations
