Fig. 2.

Diffuse rupture of the posterior annulus. Disc 8-L56 is shown. Dashed lines in the axial (A) and sagittal (B) micro-CT MIP images show the location of the micrograph (C). From the point of injection (+ in A), contrast gel has spread laterally filling the nuclear lobes (N in A). After penetrating the inner posterior annulus, the gel has spread circumferentially, flowing within the inner and mid-annular lamellae (* in A and C). Two short radial tears, connecting some of the circumferential tears, are visible in C (white arrows). Upon reaching the outer annulus, gel has flowed primarily between lamellae (black arrow in C). In both discs that suffered diffuse ruptures, the contrast gel failed to rupture the posterior longitudinal ligament (PL in C), leaving a large void (v in C) outlined in residual gel (rg in C) as it tracked circumferentially to its point of extrusion at the ligament’s left lateral margin (white arrow in A). IV inferior vertebra, ep tear of the cartilaginous endplate