Mediastinum Flashcards
What occurs at the sternal angle/T4?
Bifurcation of trachea, arch of aorta, Azygous vein into SVC, bifurcation of pulmonary trunk, L recurrent laryngeal nerve, superior border pericardium
Where do the vagus nerves pass through the diaphragm?
At the oesophageal hiatus
What is the outer layer of the pericardium?
The fibrous pericardium, attached to diaphragm and great vessels
What is the inner layer of the pericardium?
Serous pericardium - split into parietal and visceral layers
What is the epicardium?
The visceral layer of serous pericardium composed of fat and epithelial tissue
Where does the pericardial fluid come from?
The serous pericardium secretes it into the pericardial space
What is the transverse pericardial sinus?
The space behind the heart that separates the pulmonary arteries and veins.
What is the oblique pericardial sinus?
A space caused by the reflection of visceral peritoneum between where the pulmonary veins exit the heart
What is the myocardium?
The cardiac muscle layer
Where is the eustachian valve?
In between the IVC and the right atrium
Which valves of the heart have chordae tendinae?
The atrioventricular valves
What do chordae tendinae attach to?
Valve cusps and papillary muscles
What drains into the right atria?
IVC, SVC, Coronary sinus, anterior coronary vein
Where is the fossa ovalis?
In the intra-atrial septum
Describe the anterior wall of the right atria?
ridged with pectinate muscle
Describe the posterior wall of the right atria?
Smooth walled
What is the wall of the right ventricle like?
Ridged with trabecular carnae
What is the function of trabecular carnae?
To prevent the backflow of blood, contributes to the contraction force, prevents currents
How many cusps do the semi-lunar valves have?
three
What is the function of the auricular appendages?
Expand in times of increased venus return, extra capacity for the heart
Where do the coronary arteries arise from?
They come out of the ascending aorta just above the semilunar valve
When do the coronary arteries fill?
When the semilunar valve closes - diastole
Are more people left dominant or right dominant?
Right - so the posterior descending artery is from the right coronary artery
What are the branches of the right coronary artery?
Right marginal artery, posterior descending artery in 90%, acute marginal, sino-atrial branch in 60%
What are the branches of the left coronary artery?
Circumflex artery, left marginal, left anterior descending (diagonal branches)
What arteries supply the SAN?
Right coronary artery in 60% of people, Left circumflex artery in 40%
Where does the great cardiac vein run?
Alongside the LAD
Where does the small cardiac vein run?
Along the inferior border of the heart
Where does the middle cardiac vein run?
Alongside the Posterior interventricular artery
What are the venae cordis minimae/Thebesian veins?
Veins within the walls of each of the four chambers of the heart that drain blood directly into the corresponding chambers
What are the anterior cardiac veins?
Veins that drain blood from the wall of the right ventricle directly into the right atrium
Where is the crista terminalis?
On the posterior wall of the right atrium between the SVC and IVC opening
Where is the SAN found?
On the border of the SVC and crista terminalis
Sympathetic innervation to the heart comes from which spinal levels?
T1-T5
Parasympathetic innervation to the heart comes from which nerve?
Vagus
Where does the AVN lie in relation to the coronary sinus?
Superior to it
What is the ductus arteriosus?
A shunt in foetal circulation from the aorta to the left pulmonary artery
What is the ligamentum arteriosum?
The remnant of the ductus arteriosus
Which veins drain into the SVC?
Azygous, left and right brachiocephalic veins
Where do the superior intercostal veins drain into?
L - into L brachiocephalic vein
R - into azygous vein
What are the four divisions of the mediastinum?
Superior, anterior, middle, posterior
Where is the mediastinum?
The space inbetween the lungs
What are the contents of the superior mediastinum?
Thymus, trachea, oesophagus, thoracic duct, aortic arch, veins (SVC, brachiocephalic), nerves (vagus, phrenic, L recurrent laryngeal), lymphatics. (Try to eat toast and vitamins now little oliver)
What are the contents of the anterior mediastinum?
Remnants of the thymus, lymph nodes
What are the contents of the middle mediastinum?
Phrenic nerve, heart, pericardium, ascending aorta, pulmonary trunk, SVC, pericardiophenic artery
What are the contents of the posterior mediastinum?
Descending thoracic aorta, azygous vein, hemiazygous veins, thoracic duct, oesophagus, vagus nerve, sphlanchnic nerves, lymphatics (on the DATE Vivian Slapped Larry)
What do the two brachiocephalic veins join to form?
The superior vena cava
What are the three branches off the arch of the aorta?
Brachiocephalic trunk, left common carotid, left subclavian
What does the ligamentum arteriosum connect?
The arch of the aorta and the left pulmonary artery
What are the tracheal rings made from?
Fibrocartilage
Where does the transverse sinus lie?
Under the ascending aorta and pulmonary trunk
Where does deoxygenated blood enter the heart?
The right atrium via the SVC and IVC
Where does deoxygenated blood leave the heart?
From the right ventricle through the pulmonary artery
Where does oxygenated blood enter the heart?
The left atrium through the pulmonary vein
Where does oxygenated blood leave the heart?
From the left ventricle through the aorta
Which cardiac veins drain directly into the right atrium?
Anterior cardiac veins
Where do all the cardiac veins except the anterior cardiac veins drain into?
The coronary sinus
Which coronary artery does the sinuatrial nodal branch come off?
The right coronary artery in 60%. Left circumflex in 40%.
What is the limbus?
The tissue surrounding the fossa ovalis
Where is the AV node located?
In the interatrial septum superior to the coronary sinus
Where is the SAN located?
Between the crista terminalis and SVC in the right atrium
Where is the tricuspid valve?
Between the right atrium and right ventricle
Where is the mitral valve?
Between the left atrium and left ventricle
Where is the septomarginal trabecula?
On the interventricular septum
What is contained within the septomarginal trabeculae?
The bundle of His - the right side
What is the conus arteriosus/infundibulum?
The outflow tract to the pulmonary artery, in the right ventricle - smooth walled
What are the three cusps of the tricuspid valve?
Anterior, posterior, septal
What is the equivalent of the trabecular carnae in the right atrium?
pectinate muscle
where is the pulmonary valve?
Between the right ventricle and pulmonary artery
Where is the aortic valve?
Between the left ventricle and the aorta
What is the pulmonary sinus?
The pockets formed by the 3 cusps of the semilunar pulmonary valve
Where does the pulmonary valve sit in relation to the aortic valve?
Anterior, superior and to the left of it
Describe the walls of the left ventricle?
Ridged with trabecular carnae, papillary muscles attaching to chordae tendinae
Describe the walls of the left atrium?
Smooth walled, except the auricle that contains pectinate muscle, four openings for the pulmonary veins
Where do the posterior intercostal arteries come off?
The descending aorta
Where do the posterior intercostal veins drain into?
The azygous and hemi-azygous veins
Where do the grey rami lie in relation to the white rami?
White is more lateral
Which cusps of the aortic valve do the coronary arteries come out of?
Right coronary artery comes from right cusp, left from left, none from the posterior cusp
What are the cusps of the aortic valve?
Left, right, posterior
What are the cusps of the pulmonary valve?
Left, right, anterior
Is there a valve between the SVC and right atrium?
No
What are the four collateral venous systems?
Azygous, internal thoracic, long thoracic venous system with connections to femoral and vertebral veins
The thoracic duct travels through the diaphragm with which other structure?
Aorta - at T12
Where does the middle cardiac vein lie?
In the posterior interventricular septum
Which cardiac vein travels in the anterior interventricular sulcus?
The great cardiac vein
Septal papillary muscles are found within which areas of the heart?
Only the right ventricle - attached to tricuspid valve
What structure is closely associated with the root of the left lung?
Left Vagus nerve
