Sciatica
NOTE: Please be aware that causes of sciatic pain are numerous and some causes may be serious. It is best to have a licensed physician diagnose cause of sciatic pain before seeking treatment.
What is Sciatica?
Sciatica is not in and of itself a singular pathology. Sciatica or, more appropriately, sciatic pain is an uncomfortable 
nerve pain in the low back or posterior hip, then travels down the back of the leg and may extend all the way to the foot. Symptoms may be described as sharp or burning pain, as a shooting pain, or even as an electric shock. Sciatica may produce muscle weakness, numbness, tingling, or paresthesia. Interestingly, symptoms may not be continuous all along the nerve path. Some parts of the nerve may not display any symptoms at all, yet they may reappear further down the leg or foot. Sciatica may occur on only one side of the body or both, or may occur in both legs at different times for different reasons.
Causes
An evaluation should be performed by a qualified physician to determine the most likely cause of sciatic pain. Such an evaluation may include radiographic imaging — Xray, CT scan, or MRI — to determine the condition of skeletal framework of the lumbar spine. An in-depth history is taken, some orthopedic testing may be done, some form of functional movement screen may also take place. How the pain acts is often used to assess sciatic pain. From an orthopedic viewpoint, the further the nerve pain travels, the more serious the cause is likely to be. However, this is a simplistic statement and is oftentimes not very reliable for assessment purposes.
Conventional medicine usually looks at the condition of the vertebral bodies and discs of the lumbar spine (see “Anatomy” below) as the instigator of sciatic pain. Doctors look for bulging or herniated discs, bone spurring, stenosis (narrowing of openings through which nerves run), inflamed spinal ligaments, and other degenerative conditions to cause damage to, inflammation of, or compression of the spinal cord and/or sciatic nerve roots. Another possibility may be a chemical interaction between the nucleus pulposus (the gel in the center of the intervertebral disc) and the spinal ligaments which can contain epidural fat.
Causes of “sciatic type pain” but may not necessarily be considered sciatica generally turn out to be compression or entrapment of peripheral nerves by muscles, tendons, and other soft tissues along the nerve pathway. Most often, this turns out to be the piriformis muscle, located deep in the buttock. In most people, the sciatic nerve passes beneath the piriformis. In
a minority of the population (10-15%), the nerve splits and part of it passes beneath and part of it actually pierces through the piriformis. If the piriformis is tight, inflamed, or in spasm, it can compress the nerve and cause sciatic pain. In this case, the pathology can be termed “Piriformis Syndrome”.
However, true sciatica is considered to result from degenerative changes within the lumbar spine itself, whether within the central canal where the spinal cord descends, the neural foramen where the nerve roots exit the central canal, or in the zones between the central canal and the foramen.
Anatomy
Roots of the sciatic nerve originate in the spinal cord descending the spine. These nerve roots exit the spine through several outlets (neural foramen) from the L4 
vertebra in the lumbar spine to S3 in the sacrum. Sciatic roots then bundle together deep in the buttock, then run outward and downward. The sciatic nerve then runs beneath or, in some people, through the piriformis muscle. Piriformis itself attaches at the anterior border of the sacrum and again at the greater trochanter of the femur. Below the piriformis, the sciatic nerve exits the pelvis through the greater sciatic foramen, then proceeds beneath the gluteus maximus and down the back of the leg between adductor magnus (on the inside thigh) and the hamstrings before splitting into two large branches just above the knee — the tibial nerve and common peroneal nerve.
What Can Be Done?
True sciatica will likely require invasive surgery, although which surgery depends on what injury or abnormal growth has taken place within the skeletal structure. Other causes of sciatic pain may be approached by manual therapy to loosen tight structures, downregulate overactive neural activity, align the skeleton and pelvis through soft tissue and spinal segment manipulation, and muscle retraining.