Shebo,
Here is where I saw it in chirogeek and remembered I had read about it:
An annular disc tear occurs when the substance of the annulus fibrosus "rips" or "tears" and allows ... the concentric tear, which is a splitting apart of the lamellae of the annulus in a circumferential direction; and the radial tear, ...
Anular Disc Tear - General - Cached - Similar
I also googled the two and came up w/the similar information.