Exam 2 IVD Part 2 Flashcards
Why is the IVD difficult to study in its entirety?
variation in loading in different sections of the disc
What kind of force on the annular fibers results from compression of the nucleus pulposus?
tension
What movement results in compression of the anterior disc and tension on the posterior disc?
flexion
T/F: With age and exposure to biomechanical stresses, the IVD changes and becomes less fibrous.
False; becomes more fibrous
T/F: as the IVD becomes more fibrous, the flexibiltiy is diminished and more pressure is exerted on the annulus and peripheral areas of the endplate.
True
Does an injured disc deform more than a healthy one or less than?
injured disc deforms more
T/F: all viscoelastic structures exhibit hysteresis ( the absorption or dissipation of energy by a distorted structure).
True
What 3 things does hysteresis of the disc vary with?
age, level, and repetitive load
Which discs have less hysteresis?
lower thoracic and upper lumbar
T/F: hysteresis increases when successively loaded.
False; decreases
when loaded rapidly, it behaves stiffly and deforms less than when loaded slowly
What kind of force is resisted by the nucleus pulposus? by the annular fibers?
compressive forces;
tensile forces
What are the 3 types of loads imposed on the IVD?
compressive, tensile, and shear
What kind of force is applied to the IVD during flexion, extension, and/or lateral bending?
compressive and tensile
T/F: The disc is more susceptible to failure in the area of the forces of tension, not compression.
True
How does a Schmorl’s node develop?
endplate fracture from significant axial load allowing the nucleus to migrate into the vertebral body
What causes disc degeneration? What are the consequences?
supply and demand;
altered mechanics and inflammation
T/F: biomechanical behavior is dependent upon the state of degeneration.
true
T/F: the state of degeneration is independent of the age of the the disc.
False; is dependent upon the age of the disc
T/F: by the age of 50, 100% of the lumbar discs are degenerated.
False; 97%
Which segments have the most degeneration?
L3-L4, L4-L5, and L5-S1
What are the 4 stages/types of disc herniation?
nuclear protrusion, disc bulge/prolapse, extrusion, and sequestration
Which stage of disc herniation does the nucleus pulposus stay within the confines of the IVD?
nuclear protrusion
During which stage of disc herniation does the nucleus migrat outsid of the IVD, but no rupture of the annular fibers exists?
Disc Bulge/Prolapse
During which stage of disc herniation do the annular fibers tear?
extrusion
