Trigger points are localized hyperirritable areas of tenderness in a muscle. It is called a trigger point because when pressed it triggers painful response ether at the site, or the pain may be referred to other areas. Trigger points are located in a taut band of muscles fibers. The trigger point is the tenderest point in the band and is often referred to as a muscle knot. There are two basic types of trigger points: active and latent. Active trigger points cause muscular pain and will refer pain and tenderness to another area of the body when pressure is applied. Latent trigger points only cause pain when compressed; they do not refer pain to other areas of the body. Latent trigger points are one of the causes of stiff wjoints and restricted range of motion. Trigger points may be associated with myofascial pain syndromes or fibromyalgia. Some common causes of trigger points are: muscular strain, injury sustained in a fall or accident, poor posture, stress and tension, or overexertion.