TMJ & Ventilation Flashcards
List all the structures that attach to the TMJ disc
Posterior:
- inferior/superior retrodiscal lamina
Anterior:
- mandible + capsule
- superior head of lateral pterygoid
- temporal bone
Name the ligaments of the TMJ and their respective jobs
Primary:
- lateral ligament (horizontal & oblique fibers)
- stabilizes lateral aspect of capsule
Accessory:
- stylomandibular
- sphenomandibular
- helps suspend mandible from cranium
What are the osteokinematics, arthrokinematics and muscles of protrusion?
Osteo:
- anterior translation
Arthro:
- anterior slide, no rotation
Muscles:
- Masseter (bilateral)
- medial pterygoid (bilateral)
- lateral pterygoid (bilateral)
What are the osteokinematics, arthrokinematics and muscles of retrusion?
Osteo:
- posterior translation
Arthro:
- posterior slide
Muscles:
- oblique/posterior fibers of temporalis
What are the osteokinematics, arthrokinematics and muscles of lateral excursion?
Osteo:
- side-to-side translation (slight horizontal plane rotation)
Arthro:
- contralateral anterior slide of one condyle; ipsilateral condyle acts as pivot
Muscles:
- masseter (unilateral ipsilateral excursion)
- temporalis (unilateral ipsilateral excursion)
- medial pterygoid (unilateral contralateral excursion)
- lateral pterygoid (unilateral contralateral excursion)
What are the osteokinematics, arthrokinematics and muscles of depression?
Osteo:
- translates anterior and downward
Arthro:
Early Phase
- rotation (condyles roll posteriorly)
Late phase:
- slides anterior & inferior
- disc moves anterior
- limited by superior retrodiscal lamina
Muscles:
- suprahyoids (if stabilized by infrahyoids)
- inferior head of lateral pterygoid
What are the osteokinematics, arthrokinematics and muscles of elevation
Osteo:
- translates posterior and superior
Arthro:
Early phase
- initiated disc movement by superior retrodiscal lamina
- slides posterior & superior
Late phase
- rotation (condyles roll anterior)
Muscles:
- masseter (bilateral)
- Temporalis (bilateral)
- medial pterygoid (bilateral)
During elevation of the mandible what does the superior retrodiscal lamina do?
- initiates the start of pulling the disc back into the mandibular fossa
During elevation of the mandible what does the superior head of the lateral pterygoid do?
- acts eccentrically to slowing control the disc back into the mandibular fossa
How does the lateral pterygoid adjust to different bite resistances?
Low-resistance:
- intermediate disc region positioned between condyle and articular eminence
High-resistance:
- momentary reduction in joint pressure (contralateral side)
- superior head of lateral pterygoid pulls disc forward
- thicker, posterior disc between condyle and articular eminence
Walk through the steps of what happens to the TMJ disc during a full cycle of opening and closing
Opening:
- disc is still until later stage of opening when disc is pulled anteriorly by superior head of lateral pterygoid
- fully open, the disc sits between the articular eminence and mandibular condyle
Closing:
- superior head of lateral pterygoid acts eccentrically to slowly return disc back into the mandibular fossa
How does capsular fibrosis of the TMJ develop?
unresolved/chronic inflammation of fibrous capsule
- leads to overproduction of fibrous connective tissue = capsular fibrosis
Describe the sequence of events involved with TMJ internal disc derangement
Reduction:
- at rest, disc is anterior to mandibular condyle (condyle touching retrodisctal tissue, NOT disc)
- depression occurs, moves past inferior posterior disc & clicks onto disc for normal relationship (contact remains normal throughout depression)
- with elevation, condyle translates posteriorly and slips out from under the disc again (second click)
Without reduction:
- retrodiscal structures/ligaments are too lax to reduce disc to normal position
- results in block from fully opening mouth
later the click the more severe
What is Temporomandibular disorder (TMD)?
broad fake term to cover a multitude of issues associated with TMJ
Explain how a forward head posture affects the TMJ
- stretches the infrahyoid muscles
- pulls hyoid inferior and posterior (this tension is transferred to mandible via suprahyoids
- mandible is then pulled into retrusion & depression
- omohyoid places more pull on mandible via scapular attachment
What is the result of the effects of a forward head posture on the TMJ
- posterior displacement of condyles compresses retrodiscal tissues = inflammation
- lateral pterygoid pulls mandible into protrusion to avoid inflammation = spasms
- causes internal derangement of disc
How could you help a patient with chronic forward head posture?
- manual therapy if hypomobility is present
- strengthening to deep neck flexors and mid-lower traps
What are some symptoms of internal derangement of the disc?
- pain
- popping/clicking
- labored/reduced jaw movement
What is the difference between quiet and force expiration?
Quiet:
- sedentary, at rest, low metabolic demands
Forced:
- strenuous activities, rapid exchange of air
What is total lung capacity?
- total amount of air your lungs can hold
- about 5.5-6.0L
What is vital capacity?
- max volume exhaled after max inhalation
What is tidal volume?
- air moved in/out of lungs during each ventilation cycle
- at rest is about .5L
What is Boyle’s law?
- volume is inversely proportional to pressure
- EX: increase in volume = decrease in pressure
How is quiet inspiration achieved?
- diaphragm
- scalenes
- external intercostals
Explain the difference between muscles of inspiration vs expiration
Muscles of inspiration:
- increase intrathoracic volume
Muscles of expiration:
- decrease intrathoracic volume
Why is it harder to breathe in rather than breathing out?
- inspiratory muscles have to overcome the elastic recoil of the lungs and connective tissues
- quiet expiration is passive so it is easier for the body to release the air rather than pull it in
How does quiet expiration occur?
- passively from the elastic coil of lungs, thorax, and relaxing diaphragm
How does forced inspiration occur?
- diaphragm
- external intercostals (dorsal/upper regions)
- serratus posterior superior/inferior
- SCM
- levator costorum
- Latissimus dorsi
- iliocostalis throacis + cervicis
- QL
What are the indirect abdominal effects of force inspiration?
- increases intra-abdominal pressure
- compresses abdominal viscera
How does forced expiration occur?
- internal intercostals
- abdominals
- transversus thoracis
What are the direct abdominal effects of forced expiration?
- depresses ribs
- flexes thorax & sternum
Explain how the costovertebral joints move during ventilation
- AoR lies parallel with transverse processes
- upper 6 perform the pump handle motion
- lower 6 perform the bucket handle motion
What is the pump handle motion?
- more in an anterior to posterior fashion
- upper 6 ribs that are connected to the sternum
What is the bucket handle motion?
- more medial to lateral motion
- lower 6 ribs
Explain how the sternocostal joints move during ventilation
- bending/twisting of sternocostal joint cartilages
costochondral:
- permit little movement
chondrosternal:
- first rib -> very stable
- 2-7 -> synovial in nature; permits slight gliding motions
How does the rib cage keep from collapsing during inspiration?
- contraction of scalenes & external internal intercostals prevents collapsing
What is paradoxical breathing?
- describes the restriction rather than normal expanding of the rib cage
- C4 spinal cord injury = paralyzing intercostals/abdominals
- diaphragm then creates suction in chest which constricts upper thorax (especially in A&P direction)
- usually presents w/ forward protrusion of abdomen during inspiration
- intercostals will eventually become rigid & act as splint to thoracic wall
Explain the pathomechanics of COPD
- No elastic recoil -> air trapped in lungs -> thorax remains inflated (barrel chest) -> diaphragm chronically lowered -> changes resting length & line of force -> diaphragm draws ribs inward instead of lifting them outward
- often use secondary muscles for breathing
How does a closed upper extremity chain assist with breathing?
- fixes distal attachments on arms (lats, pecs minor/major) which allows use of proximal attachments to act on ribs to help with ventilation
- helps elevate sternum & ribs
What are normal ROM’s for TMJ protrusion, lateral excursion, and opening?
Protrusion: 7mm
Lateral Excursion: 9mm
Opening: 43mm
