Trigger points are defined as extraordinarily sensitive spots along the body's skeletal muscle (muscle that is attached to the bony skeleton that allows the body to move when it contracts) that are associated with palpable nodules that result from small knots of contracted muscle. Many physicians do not believe in the existence of, or importance of, trigger points and this pathology is rarely taught in medical schools. Today, physical therapists, massage therapists, occupational therapists and some chiropractors handle most treatment for trigger points.
Janet G. Travell, MD was an American physician who pioneered research on trigger points and presented her beliefs along with a colleague, David Simons, in their book that was initially published in 1983 called Myofascial Pain and Dysfunction: The Trigger Point Manual. This book suggests that up to 75% of patients in pain clinics have trigger points as their sole source of pain and that trigger points are commonly responsible for the pain that is often attributed to such disorders as carpal tunnel syndrome, bursitis, tendonitis, and arthritis. These authors proposed that trigger points are spasms of skeletal muscle due to abnormalities in the connections between nerves and these muscles. However, this theory seems unfounded since no contractions have been found by traditional EMG analysis (electromyography which evaluates the properties of muscles at rest and while contracting) and the purported trigger points are often not in the location of the neuromuscular junction.