title: MDCT demonstration of intraarticular gas in the glenohumeral joint and sternoclavicular joint with reference to arm position.
abstract: OBJECTIVE
  Our purpose was to investigate the frequency of intraarticular gas in the glenohumeral joint and sternoclavicular joint, along with the influence of the patient's arm position.
  
  
  METHODS
  Multidetector-row computed tomography (MDCT) scan on a total of 104 healthy subjects was investigated retrospectively. Raised-arm and lowered-arm positions were used sequentially, and the presence of intraarticular gas was investigated.
  
  
  RESULTS
  While the arms were in a raised position, intraarticular gas was observed in the glenohumeral joint about 9% of all subjects and in the sternoclavicular joint about 20% of all subjects. Intraarticular gas in the most subjects disappeared when the arms were lowered.
  
  
  CONCLUSIONS
  When scanning with the arms in a raised position, intraarticular gas was seen in the glenohumeral and/or and sternoclavicular joint, and disappeared in most cases when the body position was changed. Such intraarticular gas is thought to result from traction of the limbs and is considered clinically insignificant.
authors.affiliation: Department of Radiology, Graduate School of Medicine, The University of Tokyo,Bunkyo-ku, Tokyo, 113-8655, Japan. itoh-tky@umin.ac.jp
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Ito
authors.forename: Takeharu
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Naoto
authors.initials: N
authors.lastname: Hayashi
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo