Understanding Sciatica


Sciatica is a relatively common condition of pain or loss of sensation. Medically sciatica is a set of symptoms rather than a diagnosis of what is causing the pain. Sciatica means that another spinal structure is compressing a person’s sciatic nerve.

Sciatica is any pain and neurological symptoms along the nerve route, resulting in symptoms of pain, weakness, and numbness.

There are two types of sciatica:

  1. Acute sciatica, which lasts up to six weeks
  2. Chronic (persistent) sciatica, which lasts longer than six weeks

Understanding Sciatica

The sciatic nerve is the largest single nerve in the human body; it runs from each side of the lower spine, buried deep in the buttock into the back of the thigh and down the leg to the foot. It serves a vital role in connecting the spinal cord with the leg and foot muscles. Supplying information about movements of the leg and sends information about sensations back to the brain.

What happens to cause sciatica?

Any condition that may structurally affect or compresses the sciatic nerve may cause sciatica symptoms. 

  • The most common cause of sciatica is a herniated or bulging lumbar intervertebral disc. When this happens, the natural cushion between the vertebra of your spine is damaged or ruptures, causing the spinal disc to push out into areas usually occupied by nerves. Note; other terms for a herniated disc include; a slipped, ruptured, bulging or, protruding disc.
  • Lumbar spinal stenosis, which is more common in older folk, may also cause these symptoms. 
  • Spondylolisthesis – a misalignment of one vertebra relative to another may also result in sciatic symptoms.

Other causes include;

  • Muscular spasm, the sciatic nerve, can also be compressed or irritated by mechanical compression from a tight muscle, often in the buttock.
  • Inflammation may impinge a lumbar or sacral nerve root causing sciatic symptoms. The chemical ‘soup’ produced in the inflammation process is irritating in itself. Plus, the accumulation of liquid pressure in the limited space of the spinal joint can also compress the nerve.
  • An infection, abscess or tumour may also cause a mass-like effect and sciatica symptoms. 

Additional risk factors

  • Wearing high heels
  • Being overweight
  • Lack of regular exercise

The chemical ‘soup’ produced in the inflammation process is irritating in itself. Plus, the accumulation of liquid pressure in the limited space of the spinal joint can also compress the nerve.

What are the symptoms of sciatica?

Sciatica symptoms vary from person to person; for some, the pain can be severe and debilitating, while for others, the pain sciatica might be infrequent and irritating. In either case, it has the potential to get worse. Sciatica usually affects one side of the lower body. Frequently, the pain extends from the lower back to the back of the thigh and down through the leg. Depending on where the sciatic nerve is affected, the pain may also extend to the foot or toes.

Common symptoms of sciatica include:

  • Constant intense pain in only one side of the buttock or leg (rarely in both legs)
  • Pain in the buttock or leg that is worse when sitting
  • Burning or tingling down the leg
  • A cramping sensation of the thigh
  • Tingling or pins-and-needles sensations in the legs and thighs
  • Weakness, numbness, or difficulty moving the leg or foot
  • A shooting pain that makes it difficult to stand up
  • Difficulty walking

Sciatica pain often is worsened with bending forward, also known as flexion of the spine, twisting, and coughing are also irritants.

The sciatic nerve provides motor function to the back of the thigh (hamstrings), the inner thigh (adductors), and the lower leg muscles, including the calf muscles and some of the foot muscles. It helps provides sensation to the thigh, leg, lower and foot.

How is it diagnosed?

An osteopath will diagnose sciatica by taking a complete medical history and testing your back, hips, and legs for strength, flexibility, sensation, and reflexes. In some cases, it may be necessary to request imaging to help clarify if there is a specific disc injury pressing on a nerve. X-rays are not helpful in this situation/

Other tests may include:

  • MRI scans
  • CT scans
  • Nerve conduction studies to determine the health or disease of a nerve

Will I get better from sciatica?

Sciatica is not a medical emergency. However, if the next difficulty occurs; bowel or bladder function, decreased sensation around the genitals, or progressive leg weakness, this may be the sign of cauda equina syndrome, a condition the requires urgent medical review. If you have these symptoms, contact your doctor or go to A&E immediately.

Please note: This is for guidance only; it should not be considered a substitute for medical advice, diagnosis or treatment given in person by an appropriately trained health professional.

In the next post; Sciatica: Treatment


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