Spinal discs act as cushions between the bones (vertebrae) in your spine. Each disc has a soft inner core (nucleus pulposus) and a tough outer shell (annulus fibrosus). A herniated disc happens when part of the inner core pushes through a crack in the outer shell.

Not all herniated discs cause symptoms, but when they press on nerves, they can lead to pain, weakness, or numbness in the back, arms, or legs. Herniated discs are most common in the lower back (lumbar spine) and neck (cervical spine), though they can occur anywhere along the spine.

A herniated disc can result from a single injury, but more often develops gradually due to disc wear and tear. Common causes include:

• Aging – natural disc degeneration makes discs less flexible and more prone to tears

• Repetitive stress – frequent bending, twisting, or heavy lifting

• Sudden trauma – injury from falls, accidents, or sports

• Genetics – inherited traits that predispose discs to weakness

• Lifestyle factors – smoking, obesity, and lack of exercise can increase the risk

Symptoms depend on the disc’s location and whether nerves are affected. They may include:

• Back or neck pain that may radiate into the arms or legs

• Numbness, tingling, or a “pins and needles” sensation

• Muscle weakness in the shoulders, arms, or legs

• Pain that worsens with certain movements such as bending, lifting, or coughing

• Relief when lying down or resting