Trigger Points

Trigger points may be classified as potential, active, or latent and also classified as key vs. satellite and as primary vs. secondary.

There are more than 620 potential trigger points possible in human muscles. These trigger points, when they become active or latent, show up in the same places in muscles in every person. That is, trigger point maps can be made that are accurate for everyone.

An active trigger point is one that actively refers pain either locally or to another location (most trigger points refer pain elsewhere in the body along nerve pathways). A latent trigger point is one that exists, but does not yet refer pain actively, but may do so when pressure or strain is applied to the musculoskeletal structure containing the trigger point. Latent trigger points can influence muscle activation patterns, which can result in poorer muscle coordination and balance. Active and latent trigger points are also known as "Yipe" points, for obvious reasons.

A key trigger point is one that has a pain referral pattern along a nerve pathway that activates a latent trigger point on the pathway, or creates it. A satellite trigger point is one which is activated by a key trigger point. Successfully treating the key trigger point will often resolve the satellite, either converting it from being active to latent or completely treating it.

In contrast, a primary trigger point in many cases will biomechanically activate a secondary trigger point in another structure. Treating the primary trigger point does not treat the secondary trigger point.

Cause

Activation of trigger points may be caused by a number of factors, including acute or chronic muscle overload, activation by other trigger points, disease, psychological distress (via systemic inflammation), homeostatic imbalances, direct trauma to the region, collision trauma (such as a car crash which stresses many muscles and causes instant trigger points) radiculopathy, infections and health issues such as smoking.

Trigger points form only in muscles. They form as a local contraction in a small number of muscle fibers in a larger muscle or muscle bundle. These in turn can pull on tendons and ligaments associated with the muscle and can cause pain deep within a joint where there are no muscles. The integrated hypothesis theory states that trigger points form from excessive release of acetylcholine which produces sustained depolarization of muscle fibers. These sustained contractions of muscle sarcomeres compresses local blood supply restricting the energy needs of the local region. This crisis of energy produces sensitizing substances that interact with some nociceptive (pain) nerves traversing in the local region which in turn can produce localized pain within the muscle at the neuromuscular junction (Travell and Simons 1999). When trigger points are present in muscles there is often pain and weakness in the associated structures. These pain patterns in muscles follow specific nerve pathways and have been readily mapped to allow for identification of the causative pain factor. Many trigger points have pain patterns that overlap, and some create reciprocal cyclic relationships that need to be treated extensively to remove them.

Symptoms

Symptoms of a trigger point may include:

Examination

Trigger points are diagnosed by examining signs, symptoms, pain patterns and manual palpation. Usually there is a taut band in muscles containing trigger points, and a hard nodule can be felt. Often a twitch response can be felt in the muscle by running your finger perpendicular to the muscle's direction; this twitch response often activates the "all or nothing" response in a muscle that causes it to contract. Pressing on an affected muscle can often refer pain. Clusters of trigger points are not uncommon in some of the larger muscles, such as the gluteus. Often there is a heat differential in the local area of a trigger point, and many practitioners can sense that.

Treatment

Treatment for trigger point may include:

· Massage: Your caregiver may massage the muscle that contains the trigger point. They may also perform compression therapy. This is when the trigger point is pressed until the muscle relaxes. These methods help relax and stretch the muscle.

· Spray and stretch: A cooling substance is sprayed on your skin over the trigger point. This helps relax the muscle, which is then gently stretched.

· Therapeutic Modalities: Treatments such as Electrical Muscle Stimulation (EMS), Ultrasound, Combo Therapy, or Low Level Laser Light Therapy (LLLT) are used to relax the muscle, increase blood flow, decrease pain, and stimulate healing.

· Therapy: You will be instructed how to perform special exercises that will gently stretch your muscles and relieve pain. Your Athletic Trainer may also help you find the causes of your trigger points, such as poor posture or overuse.

· Medicines: Your caregiver may suggest pain medicines such as ibuprofen.

· Trigger point injections: If the previous treatments are not successful, injections may be an option. A physician injects Saline (salt solution), pain relievers, or other medicines into the trigger point. Caregivers may also use only a dry needle (no medicine). When the needle is removed, the muscle area is gently stretched.