By: Dr. Mark Bodnar, BSc, DC, FCCRS
Sciatica is a Latin term that means irritation of the sciatic nerve. The sciatic nerve is the large nerve bundle that runs from your buttock, down the back of your thigh and into your calf - all along the way branching nerves to control muscles and feeling in different parts of the leg. It originates from the spine (combined from several different spinal levels) and is a bundle of many individual nerves, each serving a different area or function. Sciatica results from either compression or inflammation of the individual nerve roots or of the sciatic nerve itself.
True sciatica can take many different forms, making the diagnosis difficult. Depending on which portion of the nerve is affected the pain can radiate to different locations in the leg. The pain is usually described as a sharp pain shooting down the leg, often right down to the foot. It can also present as a severe cramping in the leg, an area of numbness, tingling, or even as weakness in the leg muscles. "Sciatica" is just a descriptive diagnosis, so it is important to diagnose the underlying cause. Most cases of sciatica are caused by compression of the nerve roots as they exit the spine, either from a disc herniation or from stenosis.
With a disc herniation the soft disc between the vertebrae tears and bulges out into the space normally occupied by the nerve, compressing the nerve root and triggering sciatica. Stenotic nerve compression results from reduced space between the vertebrae for the nerves. Typically the available space has been gradually taken up by degenerative changes in the surrounding vertebrae, as the discs compress and the joints become arthritic.
There are many other problems that can cause similar, intense, leg pain. Injury to the lumbar discs, the muscles or joints can all refer pain into the leg without affecting the sciatic nerve. When your brain receives an overflow of pain signals from an area of injury, it may be unable to clearly decipher the signals. The brain can mis-interpret the location and source of the pain, causing a sensation of leg pain when in fact it is actually your lower back that was injured.
Muscle strain is a common cause of leg pain. The muscles of the hip and buttock classically refer pain down the back or side of the thigh and lower leg when injured, while the muscles of the lower back will refer pain into the hips or buttocks. Muscle pain often comes with predictable "trigger points" - localized areas of spasm in the muscles, which if compressed, will reproduce the pain referral. Piriformis syndrome, often mistaken for sciatica, is an irritation of the piriformis muscle in the buttocks - and usually refers pain down the posterior leg to the heel.
Disc injuries can also cause pain referral, as the disc itself is also pain sensitive. As previously noted a disc bulge or herniation can compress a nerve root and cause radiating pain. A tear of the inner disc structure will typically cause lower back pain and can refer pain into the hips and legs. Usually the pain does not progress past the knees, and is commonly aching or a sharp pain with no tingling or loss of strength.
Straining the joints in the spine and their surrounding ligaments will also refer pain into the legs. While very similar in presentation to disc injuries, joint injuries should not cause a loss of strength or loss of feeling in the leg.
These problems can be differentiated from sciatica with a thorough understanding of the anatomy, proper orthopeadic testing methods and the normal pain referral patterns. Accurate diagnosis of the pain source is important in order to allow treatment to focus specifically on the injury site rather than just addressing the pain symptoms.
If you are suffering from sciatica or back and leg pain, remember chiropractors are trained to diagnose and treat these problems.
Bedford Chiropractic, based in Bedford, Nova Scotia, offers full-service consultations, diagnosis and treatment plans for a variety of workplace, repetitive and other injuries. We treat pain to the head, neck, jaw, arm, shoulders, upper body, chest, lower back, legs and feet. Contact us today at 902 835-6865. We serve patients in the Halifax Regional Municipality, including Halifax, Dartmouth, Bedford, Sackville and surrounding areas.