Spinal manipulation is often used to treat patients with a variety of spinal disorders. Physical therapists, chiropractors, and osteopathic physicians use this technique most often.
The effects of spinal manipulation are often felt by the patient. There may be an audible pop when the procedure is done. Afterwards pain, stiffness, soreness, and other symptoms may decrease or go away. The goal of treatment is to alter the symptoms, restore joint motion, and improve movement and function.
Research shows that spinal manipulation does have a direct effect on muscle function. Specific studies have shown this to be true for the quadriceps muscle (front of thigh) and the erector spinae (muscle alongside the spine). Deep muscles of the neck and low back also respond favorably to spinal manipulation.
The exact mechanism by which spinal manipulation works is still unknown. Various theories have been proposed by many experts. There may be a direct neurophysiologic effect. However, it’s likely that there is a reflex involved. Movement of the spinal joints may just trigger an automatic response much like a knee jerk response.
Other theories include biomechanical or neuroendocrine changes. It’s also possible there is an immune system reaction and/or circulatory changes that can account for the effect of this treatment.
As imaging technology improves, more studies will be done to help identify the exact physiologic and biologic steps that occur. Studies are underway now using a new, noninvasive approach called rehabilitative ultrasound imaging (RUSI). This tool makes it possible to assess and measure deep muscle function.