What is a herniated or slipped disc? Understanding what it is requires knowledge of the anatomy of a lumbar disc and what changes occur when it herniates. First, the inside of the disc is composed of a jelly-like substance called mucoploysaccharide. Inside the jelly substance is a hard nucleus (nucleus polpusus) that acts like a ball-bearing. On the outside of the disc is a crisscrossed pattern of stretchy bands called annular fibers. The crisscrossing annular bands give the disc strength and flexibility and the nucleus rotates within the confines of the jelly substance in concert with spinal movement. The result is a divinely inspired design and the perfect pivot between two vertebras. The two vertebras with the disc in the middle are the basic components of a spinal joint.
So, the disc works like this: Imagine holding a barbell with heavy weights attached over your head. What happens? The entire disc compresses, loses height and widens like an automobile tire gone flat. Now, put the barbell down. As you bend, extend, twist or flex, so do the stretchy annular fibers on the outside of the disc. At the same time, the nucleus shifts within the jelly substance to the opposite side you are leaning. So, if you laterally bend to the right, the nucleus shifts to the left.
With an understanding of disc anatomy, we’ll talk about the bones surrounding the disc. With the two vertebras, there is the image of a disc sandwich: The vertebras are like the bread and the disc is like the meat in the middle. Now it’s time to add some important bones to the back (posterior portion) of the spinal joint. For our purposes, the most significant of these bones are the pedicle rings because they form an opening for the spinal cord. Through this opening, the spinal cord travels through the spinal joint. Of course, with a joint of any kind there’s movement. So, we can add bony (synovial, lubricating) articulations from one vertebra to another enabling movement in many directions. Most importantly, these articulations form holes (neural foramina) where nerve roots, coming off the spinal cord, exit the joint and control whatever tissues they innervate.
I specifically chose a lumbar disc for this article because it has a greater responsibility for weight bearing than any other area of the human spine because we walk upright, called bipedalism. Also, lumbar discs are also required to be very flexible.
So, what can go wrong? How does a lumbar disc herniate? Imagine this: a herniated disc is like a tire with a bubble protruding from its side. The bubble forms because rubber fibers have worn thin and pressure from air within the inner tube finds the weakest point. This analogy is very similar to a herniated disc. The jelly substance inside of the lumbar disc also has pressure. If for whatever reason some of the external annular fibers tare, a protrusion occurs, like the bubble on the side of the tire. A little bubble is like a disc protrusion and a big bubble is like a disc extrusion: two kinds of slipped or herniated discs. A disc protrusion is a very common condition and can normally be treated conservatively, such as with chiropractic adjustments. A disc extrusion is much less common and may require surgery. The most serious kind of herniated disc is called sequestration, the segmented disc. Simply stated, a portion of the disc becomes completely separated from the main body of the disc. This condition almost always requires surgery. In all these disc conditions, the herniated disc material can pin the sensitive nerve root against the bony wall of the vertebra. This, in turn, inflames the nerve root.
The signs and symptoms of a herniated disc vary with the different kinds. However, there are several common symptoms, such as antalgic posture. It’s when a person stands and walks slanted to one side like the Leaning Tower of Pisa. They lean to the side opposite the herniated disc taking pressure off the nerve root. A good sneeze often results in a sharp, breathtaking pain. After sitting awhile and then attempting to stand, the disc victim can be seen pushing up their legs in order to achieve a standing position. While trying to stand still, people with a herniated lumbar disc perform the famous low back dance swaying from side to side, weighting and unweighting from one foot to the other. And there may be other unpleasant signs, like nausea. Of course, pain radiating into one leg, and muscle spasm are very common.
These are typical symptoms of a disc protrusion, the least serious type. With a disc protrusion, symptoms come on like a cyclone, full of sound and fury. And, surprisingly, weeks later all symptoms can be entirely gone. This is not the case with a disc extrusion or disc sequestration. Symptoms persist and often worsen. Lack of bowel control and/or bladder incontinence accompanied with intractable pain at night are often experienced. But, as I mentioned, these last two are much less common.
Lumbar disc symptoms transcend typical low back pain in intensity. They’re nasty and they demand attention. In closing, here are several tips for treatment and relief. First apply ice, never heat to the low back. Ice relieves pain and is anti-inflammatory. Second, a low back support can relieve and immobilize the area. [Hint: it’s not for everybody with a disc condition.] Chiropractic adjustments are designed to restore proper spinal joint function and are known to offer a quick recovery. And in some cases, physical therapy can be effective.