Most herniated disks occur in the lower back, but they also can occur in the neck. Symptoms depend on where the disk is sitting and whether the disk is pressing on a nerve. Herniated disks often affect one side of the body.

• Arm or leg pain. If your herniated disk is in your lower back, you'll typically feel pain in your lower back, buttocks, thigh and calf. You might have pain in part of your foot as well.

  For a herniated disk in your neck, you'll typically feel the most pain in your shoulder and arm. This pain might shoot into your arm or leg when you cough, sneeze or move into certain positions. Pain is often described as sharp or burning.

• Numbness or tingling. People who have herniated disks often have radiating numbness or tingling in the body part served by the affected nerves.
• Weakness. Muscles served by the affected nerves tend to weaken. This can cause you to stumble or affect your ability to lift or hold items.

You can have a herniated disk without symptoms. You might not know you have it unless it shows up on a spinal image.

When to see a doctor

Seek medical care if your neck or back pain travels down your arm or leg, or if you also have numbness, tingling or weakness.

Disk herniation is most often the result of a gradual, aging-related wear and tear called disk degeneration. As people age, the disks become less flexible and more prone to tearing or rupturing with even a minor strain or twist.

Most people can't pinpoint the cause of their herniated disk. Sometimes, using the back muscles instead of the leg and thigh muscles to lift heavy objects can lead to a herniated disk. Twisting and turning while lifting also can cause a herniated disk. Rarely, a traumatic event such as a fall or a blow to the back is the cause.

Factors that can increase the risk of a herniated disk include:

• Weight. Excess body weight causes extra stress on the disks in the lower back.
• Occupation. People with physically demanding jobs have a greater risk of back problems. Repetitive lifting, pulling, pushing, bending sideways and twisting also can increase the risk of a herniated disk.
• Genetics. Some people inherit a predisposition to developing a herniated disk.
• Smoking. It's thought that smoking lessens the oxygen supply to disks, causing them to break down more quickly.
• Frequent driving. Being seated for long periods combined with the vibration from a motor vehicle engine can put pressure on the spine.
• Being sedentary. Regular exercise can help prevent a herniated disk.

Just above your waist, your spinal cord ends. What continues through the spinal canal is a group of long nerve roots that resembles a horse's tail, called the cauda equina.

Rarely, disk herniation can compress the entire spinal canal, including all the nerves of the cauda equina. In rare instances, emergency surgery might be needed to avoid permanent weakness or paralysis.

Seek emergency medical attention if you have:

• Worsening symptoms. Pain, numbness or weakness can increase to the point that they hamper your daily activities.
• Bladder or bowel dysfunction. Cauda equina syndrome can cause incontinence or trouble urinating even with a full bladder.
• Saddle anesthesia. This progressive loss of sensation affects the areas that would touch a saddle — the inner thighs, the backs of the legs and the area around the rectum.

To help prevent a herniated disk, do the following:

• Exercise. Strengthening the trunk muscles stabilizes and supports the spine.
• Maintain good posture. This reduces pressure on your spine and disks. Keep your back straight and aligned, particularly when sitting for long periods. Lift heavy objects properly, making your legs — not your back — do most of the work.
• Maintain a healthy weight. Excess weight puts more pressure on the spine and disks, making them more susceptible to herniation.
• Quit smoking. Avoid the use of any tobacco products.

During the physical exam, your health care professional will check your back for tenderness. You might be asked to lie flat and move your legs into various positions to help determine the cause of your pain.

Your doctor also may perform a neurological exam to check your:

• Reflexes.
• Muscle strength.
• Walking ability.
• Ability to feel light touches, pinpricks or vibration.

In most cases of herniated disk, a physical exam and a medical history are all that are needed for a diagnosis. If your health care professional suspects another condition or needs to see which nerves are affected, you may have one or more of the following tests.

Imaging tests

• X-rays. Plain X-rays don't detect herniated disks, but they can rule out other causes of back pain. X-rays can show an infection, a tumor, spinal alignment issues or a broken bone.
• CT scan. A CT scanner takes a series of X-rays from different directions. Those images are combined to create cross-sectional images of the spinal column and the structures around it.
• MRI. Radio waves and a strong magnetic field are used to create images of the body's inner structures. This test can be used to confirm the location of the herniated disk and to see which nerves are affected.
• Myelogram. A dye is injected into the spinal fluid before a CT scan is done. This test can show pressure on the spinal cord or nerves due to multiple herniated disks or other conditions.

Nerve tests

Nerve conduction studies and electromyograms (EMGs) measure how well electrical impulses are moving along nerve tissue. This can help pinpoint the location of nerve damage.

• Nerve conduction study. This test measures electrical nerve impulses and functioning in the muscles and nerves through electrodes placed on the skin. The study measures the electrical impulses in nerve signals when a small current passes through the nerve.
• Electromyogram (EMG). During an EMG, a doctor inserts a needle electrode through the skin into various muscles. The test evaluates the electrical activity of muscles when contracted and when at rest.

Besides taking the pain medicines your health care professional recommends, try:

• Applying heat or cold. At first, cold packs can be used to relieve pain and swelling. After a few days, you might switch to gentle heat to give relief and comfort.
• Avoiding too much bed rest. Staying in bed can lead to stiff joints and weak muscles — which can complicate your recovery. Instead, rest in a position of comfort for 30 minutes, and then go for a short walk or do some work. Try to avoid activities that worsen your pain.
• Resuming activity slowly. Let your pain guide you in resuming your activities. Make sure your movements are slow and controlled, especially bending forward and lifting.

Some alternative and complementary medicine treatments might help ease chronic back pain. Examples include:

• Chiropractic. Spinal manipulation has been found to be moderately effective for low back pain that has lasted for at least a month. Rarely, chiropractic treatment of the neck can cause certain types of strokes.
• Acupuncture. Although results are usually modest, acupuncture appears to ease chronic back and neck pain.
• Massage. This hands-on therapy can provide short-term relief to people dealing with chronic low back pain.

You're likely to start by seeing your family health care professional. You might be referred to a specialist in physical medicine and rehabilitation, orthopedic surgery, neurology, or neurosurgery.

What you can do

Before your appointment, be prepared to answer the following questions:

• When did your symptoms start?
• Were you lifting, pushing or pulling anything at the time you first felt symptoms? Were you twisting your back?
• Has the pain kept you from taking part in activities?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?
• What medicines or supplements do you take?

What to expect from your doctor

Your health care team might ask other questions, including:

• Does your pain travel into your arms or legs?
• Do you feel weakness or numbness in your arms or legs?
• Have you noticed changes in your bowel or bladder habits?
• Does coughing or sneezing worsen your pain?
• Is the pain interfering with sleep or work?
• Does your work involve heavy lifting?
• Do you smoke or use other tobacco products?
• How has your weight changed recently?