Mediastinum Flashcards
Mediastinum and its division
- central region between 2 pleural cavities in the thorax
- from sternal and costal cartilage anteriorly to thoracic vertebra posteriorly
- contains all thoracic organ and structure except the lungs
superior (arch of aorta, trachea, esophagus, thmus, vagus nerve, left recurrent laryngeal nerve, phrenic nerve)
anterior (inferior part of thymus, internal thoracic branches)
middle (heart, ascending aorta, pulmonary trunk, SVC arch of azygous vein, main bronchi pericardium)
posterior (esophagus, thoracic aorta, azygous and hemi-azygous vein, thoracic duct vagus nerve sympathetic trunk, splanchnic nerve)
Where is thymus
superior mediastinum
Pericardium (layers)
double-walled membrane that encloses the heart and the root of the great vessels
3 layers of pericardium
- external fibrous (tough and continuous with central tendon of diaphragm)
- internal parietal serous
- internal visceral serous
Transverse pericardial sinus
put a finger into the channel posterior to pulmonary trunk and ascending aorta, anterior to SVC
Oblique pericardial sinus
A hand placed under the apex of the heart and moved superiorly slips into the oblique sinus. SVC IVC Pulmonary veins enter the heart and are partly covered by serous pericardium which forms the oblique pericardial sinus.
Pericardium blood supply
Pericardiacophrenic artery branching very early from internal thoracic artery
Pericardiacophrenic vein branching from SVC (right) and left brachiocephalic vein (left)
They supply the pericardium wrapping the heart.
Pericardiacophrenic vein is medial to artery.
Pericarditis
inflammation of the serous pericardium
accumulation of fluid in pericardial cavity
compress on the heart (cardiac tamponade)
Treatment: Pericardiocentesis
Surfaces of the heart
anterior surface
diaphragmatic surface
left pulmonary surface
right pulmonary surface
Papillary muscle
A few papillary muscles have only one end attached to the ventricular surface, while the other end serves as the point of attachment for tendon-like chordae tendineae, which connect to the free edges of the cusps of the tricuspid valve.
Trabeculae carneae
irregular muscular ridges on the inner wall of the ventricle
Sulcus terminalis
vs
Crista terminalis
Sulcus terminalis: External feature that divide the right atrium into two
extends from the right side of the opening of the
superior vena cava to the right side of the opening of the
inferior vena cava.
Crista terminalis: internal smooth, muscular ridge that begins on the roof of the atrium just in front of the opening of the superior vena cava and extends down the lateral wall to the anterior lip of the inferior vena cava.
Coronary sulcus
separate atria from ventricle
contains left and right coronary artery, coronary sinus at the back
Structures related to or
compress on esophagus:
1) Left bronchus (anterior)
2) Aortic arch (left side)
3) Left atrium (anterior surface of
esophagus)
4) Right pulmonary veins
Ligamentum arteriosum
superior mediastinum was the ductus arteriosus. It connects
the pulmonary trunk with the arch of the aorta and allows blood to bypass the lungs during development. The vessel closes soon after birth and forms the ligamentous connection observed in the adult.
posterior to it is the left recurrent laryngeal nerve
Right vagus nerve
right recurrent laryngeal nerve goes under the right subclavian artery and up to larynx
