EXAM3_G22_Middle_Mediastinum Flashcards
Sternal angle creates what line? That separates the mediastinum into what regions?
Transverse thoracic plane
Superior and inferior regions
The mediastinum is divided into superior and inferior regions by the__________, the inferior region is further subdivided into what three regions?
Transverse thoracic plane
Anterior
Middle
Posterior
What are the contents of the middle mediastinum?
Pericardial Sac (fibrous and serous)
Heart
Roots of the great Vessels
The pericardial sac consists of two layers _________.
Fibrous- Pericardiacophrenic ligament
Serous- Parietal and Visceral pleura and pericardial cavity
The Fibrous pericardium makes up the ?
Pericardiacophrenic Ligament
The Serous Pericardium makes up the???
- Parietal and Visceral Pleura
- Pericardial Cavity :
(Serous pericardial cavity filled with fluid cushion around entire heart)- has a parietal and visceral portion- but the cavity is the lake between the two
What is the Pericardial Cavity?
The serous filled pericardial space (lake) between the visceral pericardium and the parietal pericardium.
It’s the serous cushion of the heart
Serous pericardium is surrounded by fibrous pericardium
What is the ligament that attaches the pericardium to the diaphragm?
Pericardiacophrenic Ligament made by Fibrous pericardium
- limits filling capacity of heart and has a tough outer layer
What are the two pericardial sinuses?
- Transverse pericardial sinus (aorta/pulmonary trunk)
2. Oblique pericardial sinus (IVC/pulmonary veins)
What can surgeons use to block outflow of the great vessels?
Use Transverse pericardial sinus to clamp
between Aorta/Pulmonary trunk
The potential space closed by the serous pericardium contains _____ amount of serous fluid for ______.
10-50ml of serous fluid for Lubrication
Pericarditis is the inflammation of pericardium that results in friction between _______ and _____ that sounds like walking on snow
Visceral and parietal serous pericardium
What is it called when you have excess fluid in the pericardium (over 10-50mL of serous fluid). What is bad about it?
Pericardial EFFUSION
- restricts full expansion of heart
- reduces cardiac volume and output
- Veins engorge and circulation fails eventually
What is applied pressure called?
Tamponade (tampon-ade) gross
- Restricts cardiac volume and output
- veins engorge and circulation fails eventually
What is the procedure to drain excess pericardial fluid?
Where is this done?
Pericardiocentesis
- Left 5th or 6th intercostal space near sternum or
- Infrasternal angle left of Xiphoid
Where are the two places you can perform a pericardiocentesis?
- LEFT 5th or 6th intercostal space NEAR STERNUM
2. INFRASTERNAL ANGLE (left of xiphoid)
What supplies blood to the pericardium?
What is innervation?
Bilateral:
- Pericardiacophrenic Artery (from Internal thoracic a.)
- Pericardiacophrenic Vein (drains into brachiocephalic v.)
- Innervated by Phrenic nerve
- Sensory from fibrous & parietal pericardium
Where does pericardiacophrenic artery come from and supply?
Internal thoracic artery to pericardiacophrenic a. and supplies the pericardium
What does the pericardiacophrenic artery drain and where does it drain into?
Drains blood from pericardium into the brachiocephalic v.
What nerve innervates the pericardium?
Phrenic nerve (bilaterally)
Where does sensory of pericardium come from?
Fibrous & parietal pericardium
Pericardial (diaphragmatic) pain is referred to the skin of what dermatomes?
Dermatomes 3,4,5 of ipsilateral side (RIGHT ARM PAIN)
right ear, neck, arm
What are the three tissues that make up the Heart Wall?
- EPICARDIUM (visceral pericardium)
- MYOCARDIUM (cardiac muscle)
- ENDOCARDIUM (endothelium + CT)
Where is the landmark for the apex of the heart?
LEFT 5th intercostal space
-handwidth from midsternal line-
this is the site to auscultate the apex beat
The base of the heart is formed mainly by the ______. What does it receive?
Left Atrium
receives blood from lungs via 4 pulmonary veins
What is the landmark for the Base of the heart?
Posterior at T6-T9 vertebral Levels
- Receives 4 pulmonary veins (blood from the lungs)
What are the four surfaces of the heart?
- Right pulmonary (mainly right atrium)
- Left pulmonary (mainly left ventricle)
- Anterior (sternocostal)- mainly right ventricle
- Inferior (diaphragmatic) - mainly left ventricle
Anterior (sternocostal) surface of the heart is mostly
right ventricle
Right pulmonary surface of the heart is mostly
Right Atrium
Left pulmonary surface of the heart is mostly
left ventricle
Inferior (diaphragmatic) surface of the heart is mostly
left ventricle
In an AP radiograph- Right border is mainly Inferior border is mainly Superior border is mainly Left border is mainly
RB= Right atrium
IB- Right ventricle
SB-PERICARDIAL SINUS & left atria
LB- Left Ventricle
In systole the ventricles squeeze/empty making a LUB sound. The Aortic semilunar valves and the Pulmonary semilunar valves ________. While the sound is being made as the ______ and _______ valves _________.
Aortic/Pulmonary semilunar valves open during systole
Bicuspid/Tricuspid valves CLOSE during systole which creates the LUB sound.
At the end of Systole the ____ sound is heard, Indicating that the _________ valves have opened and the _______ valves have closed.
DUB sound indicates Atrial/Pulmonary SL valves CLOSED
this also means the AV valves are opened and blood is filling the ventricles
What two valvular diseases cause pumping inefficiency?
- STENOSIS (failure of valve to open fully- slow flow)
2. INSUFFICIENCY (Prolapse)- Failure to close=backflow
Mitral valve prolapse
leaflets enlarge (floppy)= edge slips into atrium during systole
Blood flows back into left atrium and causes a murmur sound which can be auscultated
A murmur sound of the Mitral valve indicates
mitral valve prolapse- as blood flows back into the atrium during systole
Where do you listen to Aortic and pulmonary valves?
2nd Intercostal Space
- Aortic (right of sternum)
- Pulmonary (Left of sternum)
Where do you listen to Tricuspid and Bicuspid Valves?
5th intercostal Space
- Tricuspid (left of sternum)
- Bicuspid (Midclavicular line)
Fibrous skeleton of the heart anchors _______ and _____. Four fibrous rings are made by _______ which acts like an _______ to allow atria to contract separately from ventricles.
anchors Myocardium and valves
4 rings of DENSE CT act like ELECTRICAL INSULATOR
Sinu-Atrial (SA) node is located where?
Junction of SVC & Right Atrium
- initiates impulse (atrial contraction)
- ^ rate via sympathetics v rate via parasympathetics
- “Pacemaker” of heart
Atrioventricular (AV) node function? location?
delays impulse
- in Right atrium (by fossa ovalis)
AV bundle (of HIS) located?
located in fibrous skeleton
Purkinje fiber location?
Ventricular wall and in moderator band
Conduction system 1-6
- SA (ATRIA CONTRACT)
- AV
- AV bundle of His
- RL bundle branches
- purkinje fibers in moderator band
- purkinje fibers in ventricular wall
(VENTRICLES CONTRACT @ APEX)
What supplies the blood to epicardium and myocardium?
When do the arteries fill?
coronary arteries
-derived from ascending aorta
-fill during ventricular diastole
(high pressure when aortic semilunar valves close and backflow into the coronary arteries)
what artery supplies SA node? where does it come from?
SA nodal artery from right coronary artery
up and over right atrium
What artery supplies the right ventricle but doesn’t reach the apex?
Right marginal artery
What warps postero-inferiorly to the diaphragmatic surface and supplies the AV node?
AV nodal artery from the RCA
What supplies the diaphragmatic side of ventricles and IV septum?
Posterior interventricular artery from the RCA
What can lead to disruption of the normal heart rhythm?
RCA Stenosis “heart block”
What artery branches to become the Circumflex artery and left marginal artery?
LCA (runs posterior to pulmonary trunk; covered by left auricle)
What are two supplies of blood for left ventricle?
Circumflex artery (from LCA) Left Marginal Artery (from LCA)
What supplies blood to the sternocostal side of ventricles, interventricular septum, and apex of the heart?
What does it have potential to anastomose with? where?
Anterior Interventricular artery or LAD
- can potentially anastomose with posterior IV artery near apex
Right v Left Dominant heart (what more common?)
Right 65% - RCA >PIVa.
(left 25%)- LCA > PIVa
Where does blood drain in the heart?
Where located?
Coronary Sinus that drains into right atrium
Wide venous channel on postero-inferior side of heart
- Thick turd Underneath heart- drains next to IVC
What parallels LAD & Circumflex artery?
Great cardiac vein (sternocostal surface)
What parallels posterior interventricular artery?
Middle cardiac vein (diaphragmatic surface)
What parallels right marginal artery?
Small cardiac vein (sternocostal surface)
What drains into the right lymphatic duct?
Lymph from LEFT VENTRICLE
What drains into thoracic duct?
Lymph from RIGHT VENTRICLE
