title: Association of cross-sectional area of the rectus capitis posterior minor muscle with active trigger points in chronic tension-type headache: a pilot study.
abstract: OBJECTIVE
  To investigate whether cross-sectional area (CSA) of the suboccipital muscles was associated with active trigger points (TrPs) in chronic tension-type headache (CTTH).
  
  
  METHODS
  Magnetic resonance imaging (MRI) of the cervical spine was performed in 11 females with CTTH aged from 26 to 50 yrs old. CSA for both rectus capitis posterior minor (RCPmin) and rectus capitis posterior major (RCPmaj) muscles were measured from axial T1-weighted images, using axial MRI slices aligned parallel to the C2/3 intervertebral disc. A headache diary was kept for 4 wks to record the pain history. TrPs in the suboccipital muscle were identified by eliciting referred pain to palpation, and increased referred pain with muscle contraction. TrPs were considered active if the elicited referred pain reproduced the head pain pattern and features of the pattern seen during spontaneous headache attacks.
  
  
  RESULTS
  Active TrPs were found in six patients (55%), whereas the remaining five patients showed latent TrPs. CSA of the RCPmin was significantly smaller (F = 13.843; P = 0.002) in the patients with active TrPs (right side: 55.9 +/- 4.4 mm; left side: 61.1 +/-: 3.8 mm) than in patients with latent TrPs (right side: 96.9 +/- 14.4 mm; left side: 88.7 +/- 9.7 mm). No significant differences were found for CSA of the RCPmaj between the patients with either active or latent TrP (P > 0.5).
  
  
  CONCLUSIONS
  It seems that muscle atrophy in the RCPmin, but not in the RCPmaj, was associated with suboccipital active TrPs in CTTH, although studies with larger sample sizes are now required. It may be that nociceptive inputs in active TrPs could lead to muscle atrophy of the involved muscles. Muscle disuse or avoidance behavior can also be involved in atrophy.
authors.affiliation: Department of Physical Therapy, Occupational Therapy, Physical Medicine and Rehabilitation of Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain.
authors.forename: César
authors.initials: C
authors.lastname: Fernández-de-Las-Peñas
authors.forename: María Luz
authors.initials: ML
authors.lastname: Cuadrado
authors.forename: Lars
authors.initials: L
authors.lastname: Arendt-Nielsen
authors.forename: Hong-You
authors.initials: HY
authors.lastname: Ge
authors.forename: Juan A
authors.initials: JA
authors.lastname: Pareja
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009133:Muscular Atrophy / Q000473:pathology*; D009209:Myofascial Pain Syndromes / Q000473:pathology*; D053591:Referred Pain / Q000473:pathology*; D010865:Pilot Projects; D018781:Tension-Type Headache / Q000473:pathology*