Journal of anatomy
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Although age- and degeneration-related changes in the morphology and biochemistry of the annulus fibrosus have been extensively reported, studies of tensile strength changes show only a weak correlation with maturity. Given that the disc is a tissue system in which significant levels of deformation occur with normal physiological loading, there may be structure-related properties that provide a better indicator of the influence of ageing on its function. This study is a morphological investigation of lamellar interfibre cohesivity with respect to maturity. ⋯ More extreme levels of deformation in the mature tissue could result in discontinuous opening of the fibrous arrays, which might have the potential to lead to cleft formation. These clefts may, in turn, provide micropaths through which nuclear material could extrude. Importantly, with many animal studies carried out on immature discs, the results here suggest that some caution is required with respect to extrapolating annular behaviour beyond this age group.