Diaphragm and Pleurae Flashcards
What is the mediastinum?
Moveable median partition of the thoracic cavity that extends superiorly to thoracic outlet of the neck and inferiorly to the diaphragm
What are the borders of the diaphragm?
Skeletal muscles lined by pleura superiorly and peritoneum inferiorly
Borders of superior mediastinum
anterior by manubrium and posterior by vertebral bodies T1-T4
Borders of inferior mediastinum
anterior by body of sternum and posterior of vertebral bodies of lower 8 thoracic vertebrae
divisions of inferior mediastinum
anterior mediastinum- space between pericardium and sternum
middle mediastinum- pericardium and heart
posterior mediastinum- between pericardium and vertebral column
most important muscle for breathing
diaphragm
Right crus length
L1-L3/4
Left crus length
L1-L2/3
median acruate ligament
unite the crura and forms the aortic hiatus
Lateral acruate ligament
thickening of fascia (quadratus lumborum)
medial acruate ligament
thickening of fascia (psoas major)
Inferior caval hiatus level
T8
Esophageal hiatus level
T10
Aortic hiatus level
T12
innervation of diaphragm
phrenic nerve
-somatic motor
-sensory (pain and proprioception)
peripheral parts
-lower intercostal nerves (peripheral sides)
Where does diaphragm move during inhalation?
down
where does diaphragm move during exhalation?
up
Arterial supply of diaphragm
superior surface
-musculophrenic
-pericardiacophrenic (br ITA)
-superior phrenic (br thoracic aorta)
inferior surface
-inferior phrenic (br abdominal aorta)
Venous drainage of diaphragm
Superior surface
-musculophrenic
-pericardiacophrenic (drain into ITV)
-Right superior phrenic (IVC)
-some veins from posterior curvature drain into azygos and hemiazygos veins
inferior surface
-right inferior phrenic (IVC)
left inferior phrenic (IVC of left suprarenal vein)
Pleura of thoracic cavity
visceral pleura
-adhere to lung
parietal pleura
-line thoracic cavity
What is the pleural cavity?
potential space between the visceral and parietal pleura
-fluid between to decrease surface area
-allow the layers to slide over one another during respiration
Why do the lungs not fill up the entire pleural cavity?
-allow for some swelling to occur
-do not put too much pressure on the heart
-allow for fluid extraction without hitting the lungs
costodiaphragmatic recess
slit-like space between costal and diaphragmatic pleurae, along the inferior border of the lungs
*entered into during deep inspiration
costomediastinal recess
slit-like space between costal and mediastinal pleurae, along the anterior border of the lung
*entered into during deep inspiration
Thoracentesis
procedure to try and remove fluid from the pleural cavity
needle inserted into the pleural space b/w lungs and chest wall
pleural effusion
presence of fluid in the pleural space
Empyema
pus in the pleural space
hemothorax
blood in the pleural space
Pneumothorax
damage of the lung that causes air to enter the pleural cavity
-causes pressure to decrease in the lung and cause collapse
-treatment is a chest tube
Blood supply to visceral pleura
Arterial supply
-branches of bronchial and pulmonary arterial systems
Venous drainage
-azygos/hemiazygos veins and some pulmonary veins
Characteristics of bronchial arteries
-arise in thoracic arota
-1-2 for each lung
-supply oxygenated blood to nonrespiratory tissue of the lung and visceral pleura
-anastomoses occur between the capillaries of bronchial and pulmonary system
Bronchial veins
-carry about 13% of bronchial venous blood to systemic venous circuit
-the 87% left drains to pulmonary venous circuit desaturating from 100 to 99%
Blood supply of cervical pleura
intercostal vessels
Blood supply of costal pleura
intercostal vessels
Blood supply of diaphragmatic pleura
intercostal vessels (periphery) and pericardiacophrenic vessels (central tendon)
Blood supply of mediastinal pleura
pericardiacophrenic vessels
venous drainage of parietal pleura
to the companion veins of the arterial supply
nerve supply to visceral pleura
autonomic pulmonary plexus
nerve supply to cervical pleura
intercostal nerves
nerve supply to costal pleura
intercostal nerves
nerve supply to diaphragmatic pleura
intercostal nerves and phrenic nerves (central tendon)
nerve supply to mediastinal pleura
phrenic nerves
If there is a mass in the lungs, what do thoracic surgeons biopsy?
lymph nodes
what is inside the anterior mediastinum?
space between the pericardium and the sternum
What is included in the middle mediastinum?
pericardium and the heart
What is included in the posterior mediastinum?
between the pericardium and the vertebral column
When the diaphragm contracts it moves…
inferiorly
When the diaphragm relaxes it moves…
superiorly
When the diaphragm moves inferiorly, what happens?
the pressure in the thoracic cavity drops and allows for the lungs to fill with air
Where does the aorta run in the thoracic cavity? (compared to vertebral column)
right in front of the vertebral column
Referred pain from the diaphragm can be felt in…
the shoulder/trapezius area
Where does the pericardiacophrenic artery branch from? (supply the superior surface of diaphragm)
internal thoracic artery
Where does the inferior phrenic artery branch from? (supply the inferior surface of diaphragm)
abdominal aorta
What do serous membrane secrete?
fluid
What does the fluid in the pleural cavity allow?
sliding of the lung tissue
-also creates surface tension so the lungs stay open
What allows the lung to expand out during inhalation?
the surface tension between the pleura and the lung
what is the green section?
superior mediastinum
what is the yellow section?
middle mediastinum
what is the blue section?
posterior mediastinum
what is the purple section?
anterior mediastinum
which crus of the diaphragm is larger and longer?
right crus
“I ate 10 eggs at noon”
I- IVC
ate- T8
10- T10
eggs- esophagus
at- aortic hiatus
noon- T12
