I had a bad snowmobile accident and ended up with a chronic whiplash injury. My latest exam shows I have trigger points of several muscles in the upper neck. The therapist is going to work on those. What brought that on?
Scientists aren't really sure what causes painful nodules in muscles referred to as trigger points. Tissue changes associated with trigger points are palpable. There's usually a taut band of tissue. When the area is pressed or stimulated, a predictable pattern of pain is created. Lab studies of the cells involved have led scientists to believe perhaps there is a dysfunction at the motor endplate of a skeletal muscle fiber. Mechanical trauma causes a neurotransmitter called acetylcholine (ACh) to be released. When present at the junction between the nerve and muscle, ACh causes the muscle fiber to contract maximally. The muscle doesn't relax and remains tightly contracted. Blood doesn't get in or out of the area so waste from cellular metabolism doesn't get cleansed from the soft tissues. A downward cycle continues. Failure of the calcium pump occurs in the muscle and stimulates further muscle contraction. The abnormally increased calcium may cause uncontrolled muscle fiber shortening. This leads to increased metabolism. The muscle fiber shortening also cuts off local circulation. Loss of oxygen and nutrient supply to the muscle completes a vicious cycle. Thus an energy crisis occurs, and taut bands form. It appears that these taut bands are there first before trigger points develop.