To understand the origin of myofascial pain is necessary to understand two concepts: muscle tightness and trigger points (trigger points). Muscle tension is the product of two distinct factors: the tone vis-coelástico and contractile activity. The tone-lastic viscoe can be divided into two parts, the viscoelastic stiffness and elastic stiffness. The elastic stiffness is generated based on the movement, while memory foam is made in terms of speed. Contractile activity consists of three types: contracture, spasm electrogenic (pathological) and stiffness electrogenic. Contracture and electromyographic recording does not originate inside the muscle fibers. Electrogenic spasm is an involuntary muscle contraction caused pathological alpha motor neurons in the motor endplate. Electrogenic Rigidity refers to muscle tension resulting from muscle contraction in individuals who are not relaxed.

The trigger point or “trigger point” is a source of irritability in the muscle when it is deformed by pressure, stretch or contraction, which produces both a point of local pain and referred pain pattern. These trigger points can be classified into:

• Assets: when they are the direct cause of pain.
• Latent: cause dysfunction when performing certain maneuvers but not muscle pain on palpation. They are the most common and can remain dormant for long, becoming active under stress, overuse, stretching, etc.
• Parents: no underlying cause that occurs.
• Children: a nerve entrapment, radiculopathy, and so on.
• Satellites: when the trigger point remains too long without treatment and undertake adjacent structures.

Muscle pain may be associated with trigger points, muscle tension increases or combinations thereof. Myofascial syndrome is defined by the presence of trigger points, while tension headache and temporomandibular joint disorders are associated with them and increased muscle tone.

Another characteristic of myofascial pain is the presence of a palpable muscular band representing a segmental spasm of a small portion of the muscle. This band is not visible but can be appreciated by palpation after exploration of the affected muscle.

Finally, the third component of myofascial pain is referred pain, which has this name because it originates in the trigger point but is perceived distance. Can be confused with radicular pain, but usually does not follow the distribution of a nerve, or displays associated sensory or motor deficits.

The pain is usually constant, deep and dull. Sometimes they may have hyperalgesia and / or Alodia-many resembling paresthesias, requiring differential diagnosis of neuropathic pain.

Patients suffering from myofascial syndrome also accuse symptoms such as sleep disorders and weakness. Autonomic phenomena may also occur in areas of referred pain radiating as vasoconstriction, sweating and pilomotor activity.