Thorax 3 - Mediastinum & Contents Flashcards
mediastinum; middle mediastinum; pericardium
what is the mediastinum?
part of the thoracic cavity - consists of all thoracic viscera except the lungs & associated pleural cavities
what are the anterior, posterior, superior, inferior & lateral borders of the mediastinum?
anterior - sternum & 1st-5th costal cartilages
posterior - T5-12 vertebral bodies
superior - superior thoracic aperture (jugular notch, clavicles, 1st rib, T1 vertebral body)
inferior - diaphragm
lateral - mediastinal parietal pleura
what divides the mediastinum into its superior & inferior subdivisions?
transverse thoracic plane - imaginary horizontal line at the level of the sternal angle (from 2nd rib to T4/5 IVD)
the transverse thoracic plane extends from WHAT anteriorly to WHAT posteriorly
from sternal angle
to T4/5
at what vertebral level the transverse thoracic plane?
T4/5
what are the divisions of the inferior mediastinum relative to WHAT structure?
anterior, middle, posterior - relative to the pericardial sac enclosing the heart
what part of the mediastinum holds the heart?
(inferior) middle mediastinum
structures within the (inferior) middle mediastinum? (5)
- heart & pericardial sac
- origins of the great vessels (ascending aorta, SVC, IVC, pulmonary vessels)
- phrenic nerve
- pericardiophrenic vessels
- main bronchi (left & right)
pericardiophrenic vessels are contained within what division of the mediastinum?
A: superior
B: anterior
C: middle
D: posterior
C: middle mediastinum
relationship of the middle mediastinum to the anterior mediastinum?
middle mediastinum is POSTERIOR to the anterior mediastinum
what is the pericardium?
double-walled, fibro-serous sac that encloses the heart and the roots of the great vessels
what are the pericardial layers of the heart?
- fibrous (outer)
- serous (inner) - consists of a visceral & parietal layer
what are the two layers of the serous pericardium?
visceral layer (epicardium)
parietal layer
which pericardial layer adheres closest to the heart?
A: fibrous pericardium
B: serous pericardium
C: visceral serous pericardium
D: parietal serous pericardium
C: visceral serous pericardium
between what two layers is the pericardial cavity located?
A: between the fibrous & parietal layer of serous pericardium
B: between the visceral & parietal layers of the serous pericardium
C: between the visceral layer of serous pericardium & heart wall
B: pericardial cavity is between the visceral & parietal layers of the serous pericardium
function of the fibrous pericardium?
prevents overdistension and excessive movement of the heart (as a tough dense connective layer)
how is the fibrous pericardium attached to surrounding structures? (anterior, superior, inferior, lateral attachments)
INFERIOR = attached to diaphragm’s central tendon via the pericardiophrenic ligament
SUPERIOR = fuses with tunica adventitia layer of the great vessels
ANTERIOR = connects to sternum via sternopericardial ligaments
LATERAL = in contact with the mediastinal pleura and phrenic nerves
inferior surface of the pericardium is attached to WHAT surface? what ligament aids with this?
inferior surface of the diaphragm is attached to the central tendon of diaphragm - via the pericardiophrenic ligament
what layer of the great vessels is the pericardium superiorly attached to?
tunica adventitia (outer) layer of the great vessels
how does the pericardium have attachments anteriorly?
attaches to sternum via sternopericardial ligaments
what is the pericardial cavity?
potential space between the parietal and visceral layers of the serous pericardium- contains serous pericardial fluid
what type of cells produce the serous pericardial fluid?
mesothelial cells
functions/purpose of the pericardial fluid?
- lubricates heart & reduces friction between heart and pericardium
- cushioning effect against external shocks
what nerve runs in close relation to the pericardium?
phrenic nerve - runs laterally along fibrous pericardium (provides sensory innervation)