Flashcards in Exam 2 IVD Part 2 Deck (32)
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?
What movement results in compression of the anterior disc and tension on the posterior disc?
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.
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).
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.
(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?
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.
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.
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.
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?
During which stage of disc herniation does the nucleus migrat outsid of the IVD, but no rupture of the annular fibers exists?
During which stage of disc herniation do the annular fibers tear?
During which stage of disc herniation do the contents of the nucleus pulposus move into the epidural space?
During which stage of disc herniation do discal fragments break loose from the IVD and float freely in the CSF?
What kind of posture is disc herniation associated with?
extreme deviated posture (full flexion or lateral bending)
T/F: the disc bulges in the posterolateral direction of the concave side.
False; convex side (she corrected her notes in class)
T/F: crossing the legs while sitting, squatting down on the heels, lifting light weights from the ground, and rapid lunging all increase extension of the lumbar spine.
False; all these actions increase flexion of the lumbar spine