Tissue Ischemia and the Trigger Point
A MTrP is classically defined by Simons and Travell as ‘‘a hyperirritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band’’ (Simons et al., 1999).
Myofascial Pain Syndrome
Myofascial pain is a common, painful disorder that is 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.
Myofascial pain 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.