Flashcards in Lecture 4: Mechanisms of Breathing Deck (21)
Which dome of the diaphragm is higher and why?
The right due to the liver
What are the attachments of the diaphragm?
Costal margin (inferior 6 ribs and costal cartilage)
Lumbar vertebra - right crus (L1-3/4) and left crus (L1-2/3 i.e. the median arcuate ligament, medial arcuate ligament and lateral arcuate ligament
What does the median arcuate ligament arch over?
The top of the aorta
Links the left and right crura
What does the medial arcuate ligament arch over?
The psoas major
What does the lateral arcuate ligament arch over?
At what level does the IVC pierce the diaphragm?
Slightly to the right
Inside central tendon
Pulls on walls of IVC and opens it up
At what level does the oesophagus pierce the diaphragm?
Posterior to central tendon
Slightly to the left
Fibres of right crus sling around it
What nerves are the diaphragm innervated by?
The phrenic nerve C3, 4, 5
Motor to all
Sensory to central part and to pericardium
Where is pain from the central diaphragm referred to?
C3, 4, 5 dermatomes over the neck and upper limb (phrenic nerve)
Where is pain from the peripheral diaphragm referred to?
Dermatomes of the thoracic wall (intercostal nerve)
What occurs when P(atm) = P(lungs)?
No movement of air
What occurs when P(atm) > P(lungs)?
Air moves into lungs (inspiration)
What occurs when P(atm)
Air moves out of lungs (expiration)
What is the main determinant of quiet respiration?
During inspiration the diaphragm ___ and ___ the lungs.
During inspiration the diaphragm contracts and expands the lungs.
During expiration the diaphragm ___ and ___ the lungs.
___ of the lungs significantly contributes to expiration.
During expiration the diaphragm relaxes and collapses the lungs.
Elasticity of the lungs significantly contributes to expiration.
Describe the pump handle movement of the thoracic cage.
The intercostal muscles and ribs 2-6 pull the sternum forward and upward with expansion in the vertebrosternal plane, increasing AP dimension.
Describe the bucket handle movement of the thoracic cage.
Ribs 7 - 10 pull the ribs out laterally in the vertebrocondral plane increasing transverse diameter
Which accessory respiratory muscles expand the chest?
Internal intercostals (medial to costochondral junction)
Which accessory respiratory muscles collapse the chest?
Internal intercostals (lateral to costochondral junction)