What are the Intervertebral Discs in the Spine?
They are fibrocartilaginous cushions between each vertebral body and play a major role in shock absorption and mobility of the spine. They are composed of the annulus fibrosus (outer layer) and nucleus pulposus (inner layer). They are a common cause of low back pain.
How are they injured?
Excessive twisting of the lower back and forward bending can cause a ‘torsional’ stress on the disc, resulting in a tear in the annulus fibrosus. A tear will stimulate an inflammatory response and can predispose to an outward bulge of the the inner nucleus pulposus.
Compression injuries result from excessive weight bearing forces and may be initiated by fractures of the vertebrae. This can lead to degradation of the nucleus and increase load on the annulus fibrosus, which produces pain.
What does a disc injury feel like?
- Acute sudden onset of pain
- Can be triggered by a relatively minor movement e.g. bending over
- Pain may be central, on one side or across the lower back
- Pain radiate to buttocks as a ‘deep seated ache’, hamstrings, or lower leg
- May get sharp pains down the leg indicative of nerve root irritation
- Often aggravated by bending forwards and may be eased by leaning backwards