Mediastinum Flashcards
The SVC, brachiocephalic veins, arch of aorta, thoracic duct, trachea, esophagus, thymus, vagus nerves, left recurrent laryngeal nerve, and phrenic nerve are contained where?
superior mediastinum
Where is the superior mediastinum located?
between the superior thoracic aperture and the horizontal transverse thoracic plane
Where is the inferior mediastinum?
between the transverse thoracic plane and the diaphragm
What is contained in the anterior mediastinum?
remnants of the thymus, lymph nodes, fat, and connective tissue
What is contained in the middle mediastinum?
heart, roots of the great vessels, arch of azygos vein, and main bronchi
What is contained in the posterior mediastinum?
esophagus, thoracic aorta, azygos vein, thoracic duct, vagus and splanchic nerves
Where is the anterior mediastinum?
between the body of the sternum and the transversus thoracis anteriorly and the pericardium posteriorly
What is the function of the pericardium?
encloses the heart and the roots of the great vessels
Where is the pericardial sac?
posterior to the body of the sternum and the 2nd to 6th costal cartilages at the level of T5-T8 vertebrae
What is the function of the fibrous pericardium?
protects the heart against sudden overfilling
What is the pericardial cavity?
space between the parietal and visceral layers of serous pericardium
The arterial supply of the pericardium is mainly from where?
pericardiacophrenic
The nerve supply of the pericardium is from where?
phrenic nerves (C3-C5), vagus nerves (CN X), and sympathetic trunks
Where is the apex of the heart located?
posterior to the left 5th intercostal space
What are the four surfaces of the heart?
anterior (sternocostal), diaphragmatic (inferior), left and right pulmonary surfaces
What are the four borders of the heart?
right (slightly convex), inferior (horizontal), left (oblique), and superior border
From where does the right atrium receive blood?
SVC, IVC, and coronary sinus
Where is the right auricle?
projects from the right atrium, overlapping the ascending aorta
Where is the opening of the coronary sinus?
between the right AV orifice and the IVC orifice in the posterior right atrium
The _____, separates the atria and has and oval depression, the _______.
interatrial septum; oval fossa
The right atrium has a rough, muscular wall composed of _______.
pectinate muscles
Where is the opening of the SVC?
superior right atrium, at level of right 3rd costal cartilage
Where is the opening of the IVC?
inferior right atrium, almost in line with SVC at level of 5th costal cartilage
What are the irregular muscular elevations in the right ventricle?
trabeculae carneae
What is the tricuspid valve?
guards the right AV orifice
What is the function of the chordae tendineae?
prevent separation of the valve cusps and their inversion during ventricular systole (prevents from being driven into right atrium)
What is the function of the papillary muscles?
begin to contract before contraction of the right ventricle, tightening the tendinous cords and drawing the cusps together
What is the interventricular septum?
strong, obliquely placed partition between the right and left ventricles
Where is the pulmonary valve?
at the apex of the conus arteriosus at the level of the left 3rd costal cartilage
What is the left auricle?
forms the superior part of the left border of the heart and overlaps the pulmonary trunk
What are the openings of the pulmonary veins?
right and left superior and inferior, entering the posterior wall of the left atrium
What is the mitral valve?
closes the orifice between the left atrium and left ventricle, and has two cusps