Prolapsed Intervertebral Disc


In our previous article on intervertebral disc, we gave a very general idea about the condition. But I am sure that with the increasing frequency of people suffering from PID, any amount of information will seem less. So here I will help you understand what is the exact injury causing factor and mechanism.

Intervertebral disc has a central nucleus pulposus and surrounding it is a ring called annulus fibrosis. Prolapse of disc occurs when the pressure inside the disc exceeds the strength of the fibrous envelope. The anterior wall of the fibrous envelope is a lot thicker than the posterior wall, most discs prolapsed posteriorly.


This mechanism of protrusion of the inner part of the disc occurs mostly due to one of the following listed actions:

  1. Forward movement of the spine: During bending forward more pressure is taken on the front part of the disc. Due to the gelatinous consistency of the central nucleus pulposus, it is pressed towards the posterior part of the disc. Since the envelope covering that area is not as thick, prolapse occurs.
  2. Lifting heavy weights: This tends to press one vertebra against another, increasing the pressure inside the disc.
  3. Stretching the spine with the heavy weight: The increased pressure on the disc caused by bearing the weight presses the nucleus back more strongly and may lead to prolapse.

A similar effect can be produced by repeated bending-stretching movements with a lighter load or even with no load. Every such movement generates small impacts on the posterior wall of the fibrous envelope. These when done frequently may lead to a disc prolapse.

These processes occur much more readily when the muscles of the back are weak. If they are sufficiently developed, these muscles protect the disc.


The most common symptom is back pain. However if there is compression of a nerve root, radiating pain towards the limbs is also experienced.

  • Neck or upper back pain , or on lower back ,
  • Radiating pain on the arm (cervical) or on the leg (lumbar: also called sciatica).

Investigations: Plain X-rays can only identify bony abnormalities. More specialized tests include Magnetic Resonance Imaging (MRI) is ideal for diagnosing a prolapsed inter-vertebral disc.


Next time we will discuss symptoms, signs, presentations, investigations in detail. I hope I have given you all some useful information about this condition but if you want more information or have any queries, write us at Wish you best spine and joint health!