Myofascial trigger point (MTrP) (MTrP)

A myofascial trigger point (MTrP) is a hyperirritable spot within a taut band of skeletal muscle that is painful on compression and can give rise to characteristic referred pain, motor dysfunction, and autonomic phenomena (StatPearls, NBK542195). While not a single molecular target, the pathophysiology of MTrPs is widely attributed to the 'integrated hypothesis,' which involves excessive acetylcholine release at the motor endplate, leading to sustained sarcomere contraction and a localized metabolic crisis (PubMed, 15158204). This state of persistent contraction increases metabolic demand while simultaneously compressing local capillaries, resulting in ischemia and the release of sensitizing substances that activate nociceptors. Therapeutic strategies often involve physical manipulation or pharmacological agents such as botulinum toxin, which inhibits acetylcholine release, or local anesthetics that block sodium channels to interrupt the pain-spasm-pain cycle (Mayo Clinic). Understanding MTrPs is crucial for managing myofascial pain syndrome, a common cause of chronic musculoskeletal pain.

Other names

Muscle knotTrigger pointMyofascial pain syndrome focusHyperirritable spot

Pharmacological interventions typically target the underlying neuromuscular dysfunction or nociceptive signaling. Botulinum toxin inhibits the presynaptic release of acetylcholine at the motor endplate, thereby reducing sustained muscle contraction. Local anesthetics like lidocaine block voltage-gated sodium channels to inhibit signal conduction and provide analgesia. Systemic muscle relaxants may act centrally to reduce motor neuron excitability.