Myofasical Pain

Background: Myofascial pain (MP) is a common painful disorder responsible for many pain clinic visits. MP can affect any skeletal muscles in the body. Skeletal muscle accounts for approximately 50% of body weight, and approximately 400 muscles make up the body. MP is responsible for many cases of chronic musculoskeletal pain.

MP can cause local or referred pain, tightness, tenderness, popping and clicking, stiffness and limitation of movement, autonomic phenomena, local twitch response (LTR) in the affected muscle, and muscle weakness without atrophy. Trigger points (TrPs), which cause referred pain in characteristic areas for specific muscles, restricted range of motion (ROM), and a visible or palpable LTR to local stimulation, are classic signs of MP. Over 70% of TrPs correspond to acupuncture points used to treat pain.

An active TrP is an area that refers pain to a remote area in a defined pattern when local stimulation is applied. Satellite TrPs appear in response to a primary active TrP and usually disappear after the primary active TrP has been inactivated. Latent TrPs cause stiffness and limitation of ROM but no pain. Frequently, they are found in asymptomatic individuals.

Pathophysiology: A taut band in a muscle may be necessary as a precursor to development of