Sciatica is nerve pain felt due to irritation or damage to your sciatic nerve. The sciatic nerve is the largest nerve in your body, supplying sensation to the skin and controlling muscles in the back of the legs. Sciatica is typically felt as shooting pain travelling down the leg, or as a burning pain in your buttock.
The sciatic nerve is a major nerve that originates in your spinal cord then travels deep within your pelvis to emerge through a muscle in your buttocks (piriformis muscle). It then passes down the back of your legs, branching towards your feet. It is the longest and widest nerve in your body. It controls function and sensation in areas of your legs and feet, and supplies supply sensation to areas of the buttocks.
The sciatic nerve is irritated by spasms in the piriformis muscle, causing pain in the buttocks and legs.
A range of conditions can cause sciatica, by either compressing, irritating or pinching the sciatic nerve. Causes of sciatica include:
Otherwise known as a 'herniated' disc or having a 'slipped disc', it refers to damage to a disc in your spine, which causes it to protrude and potentially put pressure on the spinal cord and nerves. The spine is made up of vertebrae (the bones) and discs that are stacked on each other. They help protect the spinal cord and nerves, while providing flexibility to the spine. The discs are fibrous capsules filled with a gel-like substance. If you damage a disc, the gel leaks out and can put pressure on the nearby nerves, potentially causing sciatica.
The lumbar (lower back) vertebrae have to handle a great deal of stress during your daily activities. The discs that support your lumbar region are vulnerable to degeneration and becoming less flexible as you age. This makes them more susceptible to injury and, once injured, may result in long-term sciatica or back pain.
A herniated disc presses on the spinal nerve, resulting in pain.
This is when the spinal canal becomes narrower. This can place pressure on the spinal cord, which gives rise to pain in nerves such as the sciatic nerve. It can have numerous causes, including prolapsed discs, bony overgrowths, thickened ligaments, tumors and spinal injuries.
Cauda equina syndrome is a rare condition in which the nerves that come out of the end of your spinal cord become damaged and compressed, leading to a lack of bladder and bowel control, numbness in the 'saddle' buttock area, and weakness or paralysis of the lower limbs. This is a medical emergency that can lead to paralysis, if not immediately treated.
Your sciatic nerve can become irritated by muscle spasms in the tissues surrounding it, in particular your piriformis muscle. Your piriformis muscles are found deep within your buttock and connect the top of your thighbone (femur) to your lower spine (sacrum). These muscles stabilize your hip when you move from one foot to another and are responsible for rotating your thigh away from your body. Activities such as going up stairs, sitting for long periods and long-distance running can irritate this muscle, causing it to tighten or go into spasm and compress your sciatic nerve. Pain and numbness is felt in your buttock region and can travel down your leg. Stretching prior to running and avoiding being seated for long periods, in addition to visiting a physiotherapist to assess your condition, are often recommended.
Other reasons for sciatica include infections, a tumor growing near the nerve and injury or bleeding in the tissue surrounding the nerve.
There are some more serious conditions of which sciatica can be a warning sign. If you experience any of these symptoms, seek immediate medical attention;
Potential cauda equina syndrome signs:
Potential signs of infection or cancer:
An organ in the lower abdomen that stores urine for excretion.
A rare and serious condition in which the nerve roots at the end of the spinal cord are compressed.
Intervertebral discs - layers of cartilaginous material that act as cushions between the vertebrae and the joints in the spine, enabling the spine to bend and twist.
Entry into the body of microorganisms that can reproduce and cause disease.
An inability to move or feel; a loss of muscle function or sensation.
The bony structure in the lower part of the body trunk that connects the base of the spine to the legs. The pelvis protects important organs, such as the bladder and bowel (and in women, the uterus), and anchors thigh and abdominal muscles.
A triangular bone at the base of the spine.
A bundle of nerve tissue that runs from the brain through the spinal column and connects the brain to the body, transmitting sensory and motor signals.
A growth caused by an abnormal and uncontrolled reproduction of cells.
The cavity running through the middle of each vertebrae of the spine that contains the spinal cord.
Risk factors for sciatica include:
A metabolic disorder that is caused by problems with insulin secretion and regulation and which is characterized by high blood sugar levels. Also known as diabetes mellitus.
You may experience the following symptoms:
If you also experience any of these symptoms, seek medical attention immediately;
An organ in the lower abdomen that stores urine for excretion.
An inability to move or feel; a loss of muscle function or sensation.
Sciatica can be diagnosed from its typical pattern of symptoms. Imaging tests are usually not needed, unless your doctor is concerned about the cause of your pain, or if you have had symptoms for longer than six weeks without any change in the level of pain.
Depending on your age and symptoms, your doctor may recommend imaging tests such as an X-ray, magnetic resonance imaging (MRI) or a computerized tomography (CT) scan to confirm your diagnosis.
To rule out the possibility of a spinal infection, your doctor may also request a blood test.
A scan that uses X-rays to create a 3D image of the body. This can detect abnormalities more effectively than a simple X-ray can.
Entry into the body of microorganisms that can reproduce and cause disease.
A type of imaging that uses a magnetic field and low-energy radio waves, instead of X-rays, to obtain images of organs.
A scan that uses ionizing radiation beams to create an image of the body’s internal structures.
There are several measures you can do to help to relieve sciatica, including the following:
Treatment at home is always best discussed with your doctor or physiotherapist first to ensure it is appropriate for your specific circumstance.
Depending on the level of pain you are experiencing, you may find medication will relieve the majority of your symptoms along with rest or stretching, including the following:
A physiotherapist is an expert in how your muscles work and, in particular, how to rehabilitate them after an injury or sprain. They can assess the condition of your muscles, tendons and ligaments, then design exercise programs to strengthen them. Your physiotherapist can teach you exercises and stretching techniques that you can then use at home.
Surgery is only considered as a last resort if all other treatments have failed. All forms of surgery carry risks and these can be discussed with your surgeon before a decision is made:
Acupuncture may help to relieve pain and relax tight muscles.
A form of complementary therapy that involves fine sterilized needles being inserted into the skin at specific points to treat medical conditions.
A medication that resembles the cortisol hormone produced in the brain. It is used as an anti-inflammatory medication.
Intervertebral discs - layers of cartilaginous material that act as cushions between the vertebrae and the joints in the spine, enabling the spine to bend and twist.
An anesthetic injected into the epidural space of the spinal cord, especially used in childbirth.
Entry into the body of microorganisms that can reproduce and cause disease.
A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.
A type of medication that, when administered to an area, creates a localized loss of sensation by blocking nerve activity.
A bundle of nerve tissue that runs from the brain through the spinal column and connects the brain to the body, transmitting sensory and motor signals.
The bones that make up the spinal column.
The cavity running through the middle of each vertebrae of the spine that contains the spinal cord.
Most cases of sciatica are uncomplicated, but if your symptoms are chronic (prolonged) or if there is significant nerve compression, you may need medical or surgical intervention. Serious conditions such as cauda equina syndrome, infection or cancer will need urgent medical intervention.
A rare and serious condition in which the nerve roots at the end of the spinal cord are compressed.
Entry into the body of microorganisms that can reproduce and cause disease.
The outlook for most cases of sciatica is good. Self care, exercise and pain relief tend to be sufficient in managing symptoms. Avoiding injury, along with staying fit and healthy, are often enough to manage symptoms.
It may not be possible to avoid developing sciatica, but you can avoid activities that can lead you to injuring your back, including the following: