A slipped disc – known as a prolapsed or herniated disc – occurs when one of the discs that sit between the bones of the spine (the vertebrae) is damaged and presses on the nerves.

This can cause back pain and neck pain, as well as symptoms such as numbness, a tingling sensation, or weakness in other areas of the body.

The sciatic nerve is often affected in cases of slipped disc. It is the longest nerve in the body and runs from the back of the pelvis, through the buttocks and down both legs to the feet.

If pressure is placed on the sciatic nerve (sciatica), it can cause mild to severe pain in the leg, hip or buttocks.

Read more about the symptoms of a slipped disc.

The spine

The spine consists of 24 individual bones called vertebrae that are stacked on top of each other.

In between each vertebra there are protective circular pads of cartilage (connective tissue) called discs, which have a tough, fibrous case that contains a softer gel-like substance. The discs help maintain your back's flexibility and wide range of movement.

The spinal cord is highly sensitive and passes through the middle of the vertebral column. It contains nerve cells and bundles of nerve fibres that connect all parts of the body to the brain.

What causes a slipped disc?

A slipped disc occurs when the outer case of the disc splits, resulting in the gel inside bulging out of the disc.

The damaged disc can put pressure on the whole spinal cord or on a single nerve root (where a nerve leaves the spinal cord).

This means a slipped disc can cause pain both in the area of the protruding disc and in the area of the body controlled by the nerve that the disc is pressing on.

It is not always clear what causes a disc to break down, although age is a common factor in many cases. As you get older, your spinal discs start to lose their water content, making them less flexible and more likely to rupture.

Smoking also plays a role as it causes the discs to lose their natural flexibility.

It's important to note not all slipped discs cause symptoms such as pain, weakness or tingling. Many people will go their whole life and not know they have a slipped disc, even though they have one.

Read more about what causes a slipped disc.

Diagnosing a slipped disc

Your GP will usually be able to diagnose a slipped disc from your symptoms and medical history. They may also carry out a physical examination to test your:

• posture
• reflexes
• muscle strength
• walking ability
• sensation in your limbs

Read more about how a slipped disc is diagnosed.

Treating a slipped disc

It can take about four to six weeks to recover from a slipped disc. Treatment usually involves a combination of physical therapy, such as massage and exercise, and medication to relieve the pain.

Surgery to release the compressed nerve and remove part of the disc may be considered in severe cases, or if the pain continues for longer than six weeks.

In many cases, a slipped disc will eventually shrink back away from the nerve and the pain will ease as the disc stops pressing on the affected nerve.

Often the slipped disc will stay pressing on the nerve, but the pain goes away because the brain learns to "turn down the volume" on the pain messages coming from the nerve.

If you have a slipped disc, it is very important to keep active. Initially moving may be difficult, but after resting for a couple of days you should start to move around. 

This will help keep your back mobile and stop the joints becoming stiff and the muscles that support the spine becoming weak. Keeping moving will speed up your recovery.

Any exercise you do should be gentle and not put too much strain on your back. Exercises that involve high impact, such as running, jumping or twisting, should be avoided at first as they may cause a flare-up of the pain.

Read more about treating a slipped disc.

Preventing a slipped disc

Taking a few sensible precautions, such as leading a healthy lifestyle, can help prevent back pain and lower your risk of getting a slipped disc. For example, you should:

• take regular exercise
• use a safe technique when lifting heavy objects
• always maintain a good posture when sitting and standing
• quit smoking if you smoke

Read more about preventing a slipped disc.