Review Article

Biomechanics of Disc Degeneration

Table 1

Table lists the classification of levels of disc degeneration. Adapted from Pfirrmann et al. [28].

GradeStructureDistinction of nucleus and annulusSignal intensityHeight of intervertebral disc

IHomogeneous; bright whiteClearHyperintense; isointense to cerebrospinal fluidNormal
IIInhomogeneous with or without horizontal bandsClearHyperintense; isointense to cerebrospinal fluidNormal
IIIInhomogeneous; grayUnclearIntermediateNormal to slightly decreased
IVInhomogeneous; gray to blackLostIntermediate to hypointenseNormal to moderately decreased
VInhomogeneous; blackLostHypointenseCollapsed disc space