Many people who have a herniated disc are not aware of it because they have no symptoms of leg or back pain. Symptoms that do appear vary greatly, depending on the position of the herniated disc. If the herniated disc is:
- Not pressing on a nerve, there may be a low backache or no symptoms at all
- Pressing on a nerve, pain or numbness can occur in the area of the body leading from the nerve
- Located in the neck, pain or numbness may be felt in the shoulders, arms or chest
- Located in the lower back, sciatica may occur and cause leg pain and other nerve-related symptoms, such as weakness, numbness or tingling in one leg. Pain from a herniated disc in the lower back (sciatica) may be felt in the buttock and down the back of the leg to the ankle or foot. There may be low back pain, but it is usually not as severe as leg pain
Nerve-related symptoms of a herniated disc include:
- Tingling ("pins and needles" sensation) or numbness in one leg that can begin in the buttock or behind the knee and extend to the ankle or foot
- Weakness in certain muscles in one or both legs
- Weakness in both legs and the loss of bladder and/or bowel control, which are symptoms of a specific and severe type of nerve root compression called cauda equina syndrome. This is a serious problem that requires immediate medical help.
Other symptoms of a herniated disc may include severe deep muscle pain and muscle spasms.
Causes and Risk Factors
Herniated discs are caused by aging, degeneration of the disc (disc disease) or injury to the spine. Disc disease may result from tiny tears or cracks in the outer capsule of the disc, called the annulus. The jelly-like material inside the disc (nucleus) may be forced out through the tears or cracks in the capsule. This causes the disc to bulge, break open or break into sections.
Disc disease may develop as part of the normal aging process. After about age 30, the nucleus of a spinal disc begins to lose its fluid content, becoming less springy and more easily injured. Herniated discs can affect people of all ages, but they are most common in people between 35 and 45 years old who perform heavy manual labor or drive motor vehicles for long periods of time. Herniated discs can occur anywhere in the spine, but most occur in the lower back or in the neck region.
Injury to the spine can occur from:
- A sudden heavy strain or increased pressure to the lower back. Sometimes a sudden twisting movement or even a sneeze will force some of the jelly-like material inside the disc out through the disc's outer shell.
- Activities that are done over and over again that may stress the lower back, including poor lifting habits, prolonged exposure to vibration or sports-related injuries