title: An unusual cause of sciatic pain as a result of the dynamic motion of the obturator internus muscle.
abstract: BACKGROUND
  It has been reported that compression of the sciatic nerve because of any cause, including endometriosis, piriformis syndrome, abscess, tumor, adjoining uterus provoke sciatic pain. Some of these pathophysiologies have been diagnosed clinically and sometimes by exclusion.
  
  
  OBJECTIVE
  To discuss the clinical features of sciatic neuropathy under the belief that dynamic motion of the obturator internus muscle and tendon should be included in the differential diagnosis of sciatic neuropathy.
  
  
  METHODS
  Sciatic neuropathy, which was because of compression of the sciatic nerve caused by dynamic motion of the tendon and muscle of the obturator internus, was reported.
  
  
  METHODS
  We performed surgery to confirm the outlet of the pelvis.
  
  
  RESULTS
  Although no compression was provoked by the piriformis muscle, obvious compression was observed on the sciatic nerve by the stretched obturator internus muscle.
  
  
  CONCLUSIONS
  Although it may not be common, compression of the sacral plexus caused by dynamic motion of the obturator internus muscle should be included as a possible diagnosis for sciatic pain.
authors.affiliation: Department of Orthopaedic Surgery, Tokyo Women's Medical University, 8-1 Kawadacho, Shinjuku ku, Tokyo 162-8666, Japan. yasuaki.murata@ort.twmu.ac.jp
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Murata
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ogata
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Masatsune
authors.initials: M
authors.lastname: Yamagata
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D006801:Humans; D008160:Lumbosacral Plexus; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology / Q000502:physiology*; D009408:Nerve Compression Syndromes / Q000209:etiology* / Q000601:surgery; D010384:Pelvic Bones / Q000601:surgery; D012585:Sciatica / Q000209:etiology* / Q000601:surgery; D013710:Tendons / Q000473:pathology / Q000502:physiology*