M1-2 Class Notes Flashcards
What happens to the posterior annulus if the flexed position is maintained for many years?
- distention
- weak
- cracked
- decreased strength
What are the risks with a weakened posterior annulus?
- Herniated disc
- Decrease in tensile strength over years
- Adaptive lengthening of noncontractile tissue
What changes happen to the anterior annulus with years in a flexed position?
Becomes compressed - NP pushed posteriorly
How might long term flexed position change one’s posture after many years?
- Reduced lordotic curve
- Adaptive lengthening of posterior musculature and ligaments
- Adaptive shortening of anterior musculature and ligaments
- Structural change in posture
*Can’t be fixed in one session of tx
Because only the fibers oriented in the direction of rotation become taut, what does this mean for the layers resisting rotation?
- Only HALF of the layers are resisting rotation
- Every other layer will be taut or slackened in the same direction
What happens to the annulus during rotation and why?
- Annulus layers tighten down like a screw and approximate the vertebral bodies
- Because the layers are not elastic in nature
Which layers of the annulus tighten down during rotation?
The layers oriented in the direction of rotation
Which layers of the annulus are put on slack during rotation?
Annular layers oriented in the opposite direction
Which is the only ligament that is taut during extension?
ALL
Why is the ALL crucial to prevention of anterior slippage?
- resists body weight that is mostly distributed in the anterior L-spine
- Downhill slide of L5 of S1 caused by lumbar lordosis
What would happen if the ligamentum flavum buckled as opposed to having some elastic rebound?
Would protrude into the spinal canal and apply pressure to the SC
Ligamentum flavum: How is it positioned when the spine is in neutral?
LF is under a bit of tension
Why is the LF under tension in neutral spine?
- If you were to go into more extension, it could retract some
- Allows you to move into extension without relying solely on muscles
What would happen to the LF over time if you sit slumped?
- LF adaptively lengthens
- Lose passive support for extension
- Muscles have to work harder
Which part of bone has an easier time with nutrient absorption and why?
- trabecular
- easier for stuff to move in and out of webbing
Where is the pars located?
Where the lamina and pedicle meet
Why is the pars under constant pressure?
BW pushed through facets to prevent anterior translation
Why don’t you get anterior slippage with spondylolysis?
Rest of the vertebra holds it in place
- facets
- bony structures
- connective tissues
Rather than anterior slippage, what problems does a spondylolysis cause with respect to the contralateral side?
- Creates more load on the other side
- Increased likelihood of the same problem on the other side » spondylolisthesis
What radiographic view is used to dx a spondylolysis/spondylolisthesis?
Oblique
Which grade of spondylolisthesis is the worst? How is it determined?
- Grade 4
- determined by degree of slippage
What happens to the vertebral body/facets with bilateral spondylolisthesis?
- Inferior facet locked in place
- BW pushes vertebral body forward
Difference between “spondylitic” and “degenerative” spondylolisthesis?
- Spondylitic = pars fx
- Degenerative = articular surfaces eroded/thin » allows for anterior slippage and excessive lengthening of the pars
Increased disc height = increased ______
Movement
