title: Confirmed specific ultrasonographic findings of pulled elbow.
abstract: BACKGROUND
  Pulled elbow is a disorder commonly observed in children in routine medical practice; however, when the circumstances involved in the injury are unknown, difficulty has been encountered in differential diagnosis whether it is a bone fracture or pulled elbow. One of the reasons involved has been the unavailability of diagnostic imaging in confirming the diagnosis of the pulled elbow. Therefore, the author had performed ultrasonography for the pulled elbow and studied the specific ultrasonographic findings of the same.
  
  
  METHODS
  Using as subjects a total of 70 cases of pulled elbow, with their age ranging from 4 months to 6 years, ultrasonography was performed from September 2010 to February 2013 with the use of Hitachi EUB 7500 ultrasonographic apparatus with a 12 MHz transducer. Careful observation was made of the specific ultrasonographic images of anterior long-axis view of the radiohumeral joint before and after the manipulation.
  
  
  RESULTS
  Before the manipulation in all the cases, both the supinator muscle originating from the annular ligament and the annular ligament itself were entrapped within the radiohumeral joint, and a hypoechoic image of J-shape (J-sign) was observed. After the manipulation, the hypoechoic image of the J-shape disappeared and normal annular ligament image was observed.
  
  
  CONCLUSIONS
  Accurate diagnosis of the pulled elbow can be done by ultrasonography through the confirmation of this specific J-sign.
  
  
  METHODS
  Level IV-diagnostic studies.
authors.affiliation: Dohi Orthopaedic Hospital, Higashi Hiroshima, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Dohi
mesh_terms: D002648:Child; D002675:Child, Preschool; D004551:Elbow Joint / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007223:Infant; D004204:Joint Dislocations / Q000175:diagnosis / Q000000981:diagnostic imaging*; D008297:Male; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D000092464:Elbow Injuries