Click here to view animation. A herniated disc occurs when the intervertebral disc's outer fibers (the annulus) are damaged and the soft inner material of the nucleus pulposus ruptures out of its normal space. If the annulus tears near the spinal canal, the nucleus pulposus material can push into the spinal canal. This can cause too much pressure on the spinal cord and nerve roots. There is also some evidence that the nucleus pulposus material causes a chemical irritation of the nerve roots. Both the pressure on the nerve root and the chemical irritation can lead to problems with how the nerve root works. The combination of the two can cause pain, weakness, and/or numbness in the area of the body to which the nerve travels. For this reason, a herniated disc usually causes pain of the compressive type. Sometimes a herniated disc is referred to as "slipped disc", though the disc does not actually slip.
Herniated discs are common in the lumbar spine because of all the pressure it supports. A herniated lumbar disc often produces sciatica. This is a condition where the lower back pain and numbness radiates down the back of the leg, side of the calf, and possibly into the side of the foot. You may not necessarily have much back pain. The exact area where you will feel numbness depends on the nerve root that is affected; the numbness could be in the inner ankle, big toe, heel, outer ankle, outer leg, or a combination of them. Your doctor can use this information to get an idea which nerve is affected.
Pressure on the nerve root can cause the parts of the nerve that control the muscles not to work properly. This can result in weakness of some muscles and may change the reflexes in certain areas. Again, your doctor can use this infor mation to try to determine which nerve is involved.
The same is true for the neck. A problem stemming from the neck may result in pain that is perceived in the arm or hand. However, a herniated disc is much less common in the thoracic spine. This is likely because the discs are much thinner and there is less material in the nucleus pulposus to rupture into the spinal canal. HOWEVER, if a herniated disc does occur in the thoracic spine, it can be much more serious than in the lumbar spine. The thoracic spine has very little extra room in the spinal canal. In addition, a herniated disc in the thoracic spine puts pressure on the spinal cord - not just a few nerve roots. Too much pressure on the spinal cord from a herniated thoracic disc can lead to total paralysis from the waist down.
Just because a disc has herniated does not necessarily mean that you will need to undergo surgery. In most cases, a herniated disc can be treated without surgery. The treatment of a herniated disc depends on the symptoms. It also depends on whether the symptoms are getting steadily worse -- or whether they are getting better. If the symptoms are getting steadily worse, your doctor may be more likely to suggest surgery. If the symptoms are getting better, your doctor may suggest watching and waiting to see if the symptoms go away. In many cases, the initial problems due to a herniated disc completely resolve over several weeks to months.
In rare cases, a herniated disc in the lumbar spine area can be so large that it fills the entire spinal canal in the area where it ruptures. When the spinal canal fills with disc material, it may place a great amount of pressure on the nerves. If this occurs in the lower spine, it can lead to a condition called "cauda equina syndrome". This problem can lead to permanent paralysis of the muscles that control your bowels and bladder. If you lose control over your bladder or bowels, you should contact your health care provider immediately. These symptoms require immediate medical attention.