Flashcards in Mechanics of Ventilation Deck (33):
Functions of thorax
Move with ventilation
What happens to the thorax as you age?
It widens and looses compliance (stiffer)
Loose AP diameter, ribs become more horizontal
Which ribs only articulate with 1 vertebral body?
1, 10, 11, 12
Is the thorax open chain or closed chain?
Closed chain, excluding ribs 11 and 12 (open chain)
What do ribs articulate with?
Bodies, transverse processes and disc;
1, 10, 11, 12 with facets of body only
What is the axis of motion through in the Ribs?
Through the CV and the CT joints
What plane is the axis of rotation for the upper ribs?
close to the frontal plane
What plane is the movement for the upper ribs in?
What plane is the axis of rotation for the lower ribs?
close to the sagittal plane
What plane is the movement for the lower ribs in?
What can the upper and lower ribs be compared to?
Upper ribs = pump handle
lower ribs = bucket handle
Ribs 1-10 articulate posteriorly with vertebral bodies by what joint(s)?
2 synovial joints: CV and CT
Describe the osteokinematic motion of the ribs:
ribs moving on the vertebral spine
Describe the expansion of the ribs:
doesn’t incorporate movement of the bones
Central tendon of diaphragm is
Displacement of the diaphragm causes _______ , which draws air in.
The diaphragm shortens during ______.
At rest, diaphragm muscle fibers are oriented ______.
What muscles are primary muscles of inspiration?
When do scalenes have optimal length-tension?
(remember, they attach to cervical vertebrae-ribs 1/2 and act to lift thorax up)
What are the accessory muscles of inspiration?
SCM, upper traps, serratus anterior, pec major/minor (reverse action), lats(reverse action)
When does the SCM kick in?
assists during inspiration with pathology or exertion
With a T3 SCI, what position makes breathing easier?
supine: abdominal contents have external support of table (could also use abdominal binder in seated)
What adaptations occur with hyperinflated lungs during inspiration?
increased lateral excursion, trap elevation. adaptations due to decreased contractility of diaphragm and chest wall due to length-tension changes.
What are the muscles of expiration?
abdominals (rectus, external, internal, transverse), triangularis sterni, QL
Describe the general results of expiration:
passive, thorax returns to resting state, diaphragm returns to dome shape, abdominal contents return to starting position
Describe the biomechanics of breathing:
diaphragm contracts, ↑ intra-abdominal pressure, ↑ thoracic volume vertically/transversely, ↓ intrathoracic pressure
Upward & outward motion of lower ribs is called
→ bucket handle motion
A/P motion of upper ribs is called
→ pump handle motion
What are the 3 phases of a cough?
1. deep inhalation
2. isometric contraction
3. forced expiration
What muscles are involved in cough?
rectus abdominus, transverse abdominus
What are consequences of ↑ WOB?
↑ levels of 02 demand, ↑ recruitment of accessory muscles, ↑ 02 COST OF VENTILATION
(these are result of pathology)