Common Conditions
Disc Herniation
Symptoms, Common Causes and Treatments
Understanding Disc Herniation
Disc herniation refers to a condition where the inner substance of the lumbar intervertebral disc (nucleus pulposus) is displaced outwards through the outer substance (anulus fibrosus). People often remember an event which precedes the onset of pain. While the most common cause of herniated disc is ageing due to degenerative changes at the nucleus pulposus. The second most common cause is trauma. Repetitive trunk bending and twisting with load, sedentary lifestyle, poor posture are found to be associated with disc herniations. Most cases of herniated disc occur within the age of 30-50, and about 95% of herniated discs occur in the lower lumbar region (e.g. L4/5, L5/S1).
Symptoms
Lumbar disc herniations can cause low back pain, and the pain may radiate down one side of the lower extremities for some instances due to peripheral nerve irritation by the herniated discs. In the more severe cases, the patient may even report numbness and weakness in the lower extremities.
- Low back pain that may worsen with bending or twisting
- Unilateral leg pain (sciatica‑like), tingling, burning, or pins‑and‑needles
- Lower‑limb weakness or feelings of heaviness/instability
- Directional preference: certain movements relieve symptoms; the opposite aggravates
- Acute stage: trunk movements in multiple directions can provoke pain/numbness
- Later stage: back bending (extension) is often better tolerated and may reduce disc pressure
- Monitor neurological signs closely, especially new or worsening numbness and weakness.
Causes and Risk Factors
The causes of disc herniation include natural degeneration, improper posture and external trauma, as well as poor lifestyle habits. The following are the main contributing factors:
- Age‑related degeneration of the disc (most common cause)
- Trauma or sudden overload (e.g., heavy lifting with twist)
- Repetitive flexion/rotation with load; prolonged sitting
- Poor posture and low activity levels
- Suboptimal lumbopelvic control: weak core/hip muscles, limited thoracic mobility
- Previous episodes of low back pain
Why do some people develop herniated discs from the same movements while others do not?
It results from the interplay of three factors: structural vulnerability, load exposure, and motor control. When a disc is already degenerated, subjected to high-intensity or high-frequency loads, and lacks sufficient core and hip stability, the annulus fibrosus is more prone to microtears and fissures, ultimately leading to nucleus pulposus displacement.