26/06/2019
PA Geeks! Some of you will be doing Pilates for disk injuries. Below is some information from Kapanji "The physiology of the joints." Enjoy!
The various types of disc prolapse
When compressed axially, the substance of the nucleus pulposus can stream out in various directions.
If the fibers of the annulus fibrosus are still strong enough, the increased pressure within the nucleus can cause the vertebral discal surfaces to give way. This corresponds to intervertebral prolapse (Fig. 91).
Recent studies have shown that the annulus fibers start to degenerate after 25 years of age, leading to tears within its various bundles. Therefore, under axial stresses, the nuclear material can stream out through the torn fibers of the annulus (Fig. 92) in a concentric or more often radial fashion. The prolapse of nuclear material anteriorly is among the rarest, whereas posterior prolapse and particularly posterolateral prolapse are almost the rule.
Therefore, when the disc is crushed (Fig. 93), part of the nuclear substance escapes anteriorly, but more likely posteriorly and can thus reach the posterior edge of the disc to emerge under the posterior longitudinal ligament (Fig. 94).
After the annulus is split (A), a streamer from the nucleus, still attached to it, can remain trapped under the posterior longitudinal ligament (B), whence it can be brought back by vertebral traction, but more often it snaps the posterior longitudinal ligament (C) and may even come to lie free within the vertebral canal, i.e. the free of migrating type of disc prolapse (D). In other cases, the nuclear streamer stays trapped under the posterior longitudinal ligament (E) and gets nipped off by the fibers of the annulus, which snap back into position and preclude any return to normal.
Finally, in other cases, the streamer reaches the deep surface of the posterior longitudinal ligament and glides inferiorly or superiorly (F). This corresponds to the migrating subligamentous prolapse.
It is only when the prolapse disc presses against the deep surface of the posterior longitudinal ligament that nerve endings within the ligament are stretched causing lumbago or a sprained back.
Finally, compression of the nerve root by the pr*****ed disc causes nerve root pain, which has different names according to its location. For example, it is called sciatica when the sciatic nerve is involved. The term lumbago-sciatica is often used since at the start the sciatica is associated with low back pain.