Sciatica - Lower Back Pain, Function, Disorder, Treatment, Precautions
Know your Body

Understanding Sciatica - Pain in the Lower Back

Dr.Surya Rao Poodipeddi profile Authored by Dr.Surya Rao Poodipeddi on 10 Mar 2014 - 14:24.

Similar to brachial plexus which serves both the upper limbs, the Sciatic nerve serves both the lower limbs.

The sciatic nerve is the largest single nerve in the human body and is almost as thick as the circumference of a finger and runs from each side of the lower spine through deep in the rear and the back of the thigh traveling all the way down to the foot giving off branches to each part in the thigh, knee, leg, ankle and the foot. It connects the spinal cord with all the muscles in the respective lower limb. 

The sciatic nerve is a combination of nerves consisting of fourth and fifth lumbar nerves and the first three nerves in the sacral spine. Each of these nerves emerge from the openings in the respective vertebra and join together like a plexus ultimately ending up as a large and thick nerve called the sciatic nerve. There are two sciatic nerves one for each lower limb.  

Function: The main function of the sciatic nerve is to supply sensation and strength to the lower limb including control of reflexes in the limb. It connects the spinal cord with the outside of the thigh, muscles in the back of the thigh known as hamstring muscles and all the muscles in the lower portion of the limb including the foot. It therefore becomes obvious that any impairment in the sciatic nerve could lead weakness in the muscles and/or numbness or tingling.

Sciatica disorder: is the commonest condition seen when the sciatic nerve is affected for whatever reasons, normally seen among those in the middle age group. The severity of sciatica depends on the extent of involvement of the sciatic nerve and the cause for it.

Sciatica commonly refers to a pain that radiates along the sciatic nerve and is typically felt in the rear, below the back of the leg and possibly the foot. Sciatica is one of the most common forms of pain due to the compression of the spinal nerves.

Sciatica is only a symptom and can never be a diagnosis, because the latter is determined by locating where exactly the nerve is compressed and what causes such a compression like prolapsed intervertebral disc or an injury to the spinal nerves forming the sciatic nerve.

In majority of cases a simple irritation to the nerve will get better with time and conservative line of treatment. However, a severe pain not relieved by conventional line of treatment might be due to a serious injury to the nerve requiring methodical investigations and surgical procedures.

Usually sciatica affects one side of the body. The pain may be dull, sharp, tingling or may be accompanied by intermittent episodes of shooting pain beginning in the buttock and traveling to the back of thigh or leg. The pain may travel up to the feet via the knee. The patient may feel tingling and numbness. Any attempt to sit or trying to stand up may give rise to severe pain leading to inability to accomplish them. In some cases straining to sneeze or cough might induce severe pain.

Other major disorders known to cause sciatic nerve compression include:

  • Herniated disc, commonly known as PID (Prolapsed Intervertebral Disc)
  • Degenerative disc disease ( a natural biological process associated with aging)
  • Lumbar Spinal Stenosis  (narrowing of one or more passages through which the nerves travel)
  • Isthmic Spondylolisthesis resulting from a stress fracture often involving the 5th lumbar vertebra.
  • Spinal tumors and infections are other important causes for sciatica though relatively rare.

Treatment includes both non-surgical and surgical. The former includes use of non-steroidal anti-inflammatory drugs, bed rest, short term use of narcotic group of drugs, in very severe cases and physiotherapy. Every patient need not undertake surgical intervention. Only those who don’t get relief in 4 to 6 weeks despite conservative line of treatment with rest and, drugs and physiotherapy may need a thorough evaluation including an MRI to decide the need for surgical intervention.

Whatever be the type of treatment chosen it is essential to follow simple precautions like:

  • Alternate resting of one foot on a stool while standing,
  • Using a pillow or a rolled up towel behind the back while driving a car
  • Using a pillow under the knees while sleeping on the back or between the knees if lying down on the side.
  • Eating healthy food, maintaining optimum weight and giving up smoking may go a long way in helping the health of the spine.
*Disclaimer: This is not medical advice. The content is for educational purposes only. Please contact your doctor for any health care issues.