myofascial trigger point

Introduction

A well localized point of tenderness with radiation of pain to specific zones. Myofascial trigger points are diagnostic criteria for myofascial pain syndrome & fibromyalgia syndrome.

Etiology

• muscle hyperirritability
• muscle strain
  • mechanical stresses
    • structural asymmetry
      • leg-length discrepancy
      • pelvic asymmetry
      • short humerus
    • poor posture
    • prolonged immobilization
  • nutritional deficiency
  • endocrine disorders, especially thyroid
  • emotional stress/distress
  • sleep disturbance

Epidemiology

• up to 50% of normal population
• male:female ratio 1:1

Clinical manifestations

• some trigger points have associated epiphenomena
  • sternocleidomastoid
  • lacrimation
  • rhinorrhea
• pain & dysfunction specific to the affected muscle
• palpation of the trigger point reproduces or accentuates the pain
• commonly encountered trigger points
  • center of a muscle belly (most common)
    • paravertebral trigger points, associated with low back pain
  • costosternal junction
  • xiphoid process
  • ligamentous & tendinous insertions
  • fascia
  • fatty areas
• referral of pain (see myofascial pain syndrome)

Additional terms

• fibromyalgia syndrome (fibromyositis, fibrositis)
• myofascial pain syndrome
• trigger point injection