Intervetebral disc

In simple terms, the intervertebral disc is a nucleus surrounded by an outer layer which resembles a jelly filled donut.   If you apply pressure to the front of the disc, the nucleus will move in the opposite direction to the back.  The outer layer (annulus fibrosus) is composed of 10 to 20 concentric collagen layers which surround the nucleus.  When we are moving, the intervertebral disc acts like shock absorbers which restrain movement and partially stabilizes the vertebrae above and below.  It has very strong resistance to vertical, horizontal and sliding movements but limited resistance to twisting.




The spine is made up of vertebrae, intervertebral disc and the spinal cord.  The intervertebral discs are sandwiched between the vertebrae and the spine in located within the vertebrae.  There are also ligaments and muscles to stabilise the spine.



Protusion vs herniated disc (prolapsed disc, ruptured disc and slipped disc)

Protusion is when the nucleus (jelly) is getting pushed outwards but hasn’t torn through all the layers.  A herniated disc is when the nucleus (jelly) gets through all the layers.



Herniated disc

You can have a herniated disc anywhere in the spine from the neck to the low back.  They generally occur in the low back, then in the neck and rarely in the thoracic spine (mid back).  To simplify, I will speak of the low back or lumbar spine.

A herniated disc doesn’t usually happen on the first incident.  It is usually more of a wear and tear of the outer layer of the intervertebral disc where it is stretched and thins which eventually breaks through it.   At this point, there is a possibility that it can put pressure on the nearby nerve causing nerve symptoms.




–          Age related degeneration of the annulus fibrosus

–          Trauma

–          Lifting injuries

–          Straining a muscle

–          Genetics

Due to the release of inflammatory chemical mediators, the tear will often cause severe pain even if there is no nerve root compression.


Signs and symptoms:

They are very varied due to the level of injury.  Typically, the symptoms are only on one side of the body.

–          Back pain from minor to severe (usually continuous) and sometimes no pain at all

–          Pain in thighs, knees or feet

–          Numbness

–          Tingling

–          Muscular weakness

–          Paralysis

–          Paresthesia

–          Affection of the reflexes


–          anti-inflammatory medication and pain killers

–          physiotherapy

–          avoiding painful movements

–          surgery

–          time

–          proper posture/movements ( the graph shows the load on the low back depending on the position)


–          core strengthening

–          heat

–          keep moving (the pain is usually worsened by prolonged sitting, bending, or simply staying in any one position for too long)

–          steroid injections


With a disc bulge, the healing time is usually shorter but it can still take months.  With a disc herniation it can take many months or even years to resolve.

The single biggest factor in healing is not stressing.  You want to maintain your physical fitness, range of motion and strength to the best of your ability without aggravating the pain.  Aggravation of the pain probably means that you have pushed the wall of the disc further again, worsening the bulge.

How to prevent

–          Protect your back when you lift.  For example, lift with your legs, NOT your back.  Don’t bend forward at the waist when you lift.  Bend your knees and squat.

–          Use good posture.  When you stand or walk, keep your shoulders back and down, your chin back, and your belly in.   This will help support your lower back.

–          Get regular exercise

–          Stay at a healthy weight.  This may reduce the load on your lower back.

For more information or if you have any questions on back issues or disc bulges, please contact or your family physician for more details.