Likely Explanations for Clinical Features of Myofascial Trigger Points

TABLE 5. Likely Explanations for Clinical Features of Myofascial Trigger Points

Clinical Features Likely Explanation

Palpable Band Continuous abnormal release of calcium from sarcoplasmic reticulum
Spot Tenderness Sensitization of nociceptors in the vicinity of the motor endplate
Jump Sign Severity of spot (trigger point) tenderness
Pain Recognition Digital pressure is aggravating trigger points that are responsible for patient's pain
Twitch Response A spinal reflex activation of motor units whose endplates have developed active loci and/or a mechanically elicited axon reflex of those same motor units
Referred Pain and Excitation of 'sleeping' nociceptors
Tenderness input from TrP (Refs: 78, 79)
Restricted Range Increased release of acetylcholine of Motion in neuromuscular junctions of active loci due to mechanical stress with related release of sensitizing substances locally
Muscle Weakness Reflex inhibition of involved muscle