Dr Adriaan Liebenberg My Spine Explained | Page 25

nucleus pulposus
annulus fibrosus
disc prolapse
A
B
disc extrusion
disc sequestration
C
D
Figure 4.1
The four stages of disc damage, leading to herniation (prolapse) of disc mate-
rial.
A: Annular tear: At this stage the disc is intact and there is only a small tear
in the tough outer layer (annulus fibrosus).
B: Disc prolapse: The soft centre of the disc (nucleus pulposus) is starting to
protrude from its normal position, but is still contained within the outer layer.
C: Disc extrusion: At this stage the soft nucleus is extending beyond the annu-
lus fibrosus.
D: Disc sequestration: The nucleus has burst through the annulus fibrosus
and a piece of the nucleus has broken off from the rest and is lying loose in
the spinal canal.
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