The term sciatica describes the symptoms of leg pain—and possibly tingling, numbness or weakness—that originate in the lower back and travel through the buttock and down the large sciatic nerve in the back of the leg.
Usually, sciatica only affects one side of the lower body and the pain often radiates from the lower back all the way through the back of the thigh and down through the leg.
Sciatica (sometimes known as radiculopathy) is a description of symptoms, not a diagnosis. A herniated disc, spinal stenosis, degenerative disc disease, and spondylolisthesis can all cause sciatica.
Some combination of the following symptoms is most common:
Lower back pain, if experienced at all, is not as severe as leg pain
Constant pain in only one side of the buttock or leg, but rarely both the right and left sides
Pain that originates in the low back or buttock and continues along the path of the sciatic nerve - down the back of the thigh and into the lower leg and foot
Pain that feels better when patients lie down or are walking, but worsens when standing or sitting
Pain that is typically described as sharp or searing, rather than dull
Some experience a "pins-and-needles" sensation, numbness or weakness, or a prickling sensation down the leg
Weakness or numbness when moving the leg or foot
Severe or shooting pain in one leg that may make it difficult to stand up or walk
Depending on where the sciatic nerve is affected, the pain and other symptoms may also include foot pain or pain in the toes.
Lumbar herniated disc
A herniated disc occurs when the soft inner core of the disc (nucleus pulposus) leaks out, or herniates, through the fibrous outer core (annulus) and irritates the contiguous nerve root.
A herniated disc is sometimes referred to as a slipped disc, ruptured disc, bulging disc, protruding disc, or a pinched nerve. Sciatica is the most common symptom of a lumbar herniated disc.
Lumbar spinal stenosis
This condition commonly causes sciatica due to a narrowing of the spinal canal. Lumbar spinal stenosis is related to natural aging in the spine and is relatively common in adults over age 60.
The condition typically results from a combination of one or more of the following: enlarged facet joints, overgrowth of soft tissue, and a bulging disc placing pressure on the nerve roots, causing sciatica pain
The sciatic nerve can get irritated as it runs under the piriformis muscle in the buttock. If the piriformis muscle irritates or pinches a nerve root that comprises the sciatic nerve, it can cause sciatica-type pain.
This is not a true radiculopathy (the clinical definition of sciatica), but the leg pain can feel the same as sciatica caused by a nerve irritation.
Degenerative disc disease
Sacroiliac joint dysfunction