title: Accuracy of measuring tape and vertebral-level methods to determine shoulder internal rotation.
abstract: BACKGROUND
  Goniometers can be used to assess shoulder ROM with reasonable accuracy, but not internal rotation. Vertebral level, as determined by the hand-behind-the-back method, is used frequently but its reproducibility is questionable. We therefore devised a new measuring tape-based method for determining vertebral level.
  
  
  OBJECTIVE
  We (1) compared the accuracy of a measuring tape-based and conventional vertebral-level method; (2) determined whether BMI affects their accuracy; and (3) devised a formula for converting distances measured using a measuring tape to vertebral levels.
  
  
  METHODS
  We assessed internal rotation in 61 patients with shoulder pain. An electrode was taped to the skin where the thumb reached maximally behind the back. The vertebral-level method involved determining the vertebral level of the electrode by palpating bony landmarks whereas the measuring tape method involved measuring the distance between the C7 spinous process and the electrode. True vertebral levels of the electrode were confirmed by radiography.
  
  
  RESULTS
  In nonobese patients, the accuracies of the upper thoracic and lumbar-level measurements were better for the measuring tape method than the vertebral-level method (r = 0.861 and 0.700, respectively in upper thoracic; 0.913 and 0.710, respectively in lumbar). Patient BMI affected the accuracy of the vertebral-level method but not that of the measuring tape method. The distances obtained using the measuring tape method could be converted into vertebral-level units using the formula: estimated vertebral level = 0.031 × [distance between C7 spinous process and thumb behind back] - 0.044 × [patient height] + 7.277.
  
  
  CONCLUSIONS
  The measuring tape-based method reflected shoulder internal rotation with higher accuracy than the vertebral-level method, and unlike the vertebral-level method, the measuring tape method was not affected by obesity.
  
  
  METHODS
  Level II, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Surgery, Ajou University, School of Medicine, san 5, Woncheon-dong, Yeongtong-gu, Suwon 443-721, Korea.
authors.forename: Seung-Hwan
authors.initials: SH
authors.lastname: Han
authors.forename: Kyung-Soo
authors.initials: KS
authors.lastname: Oh
authors.forename: Kyeong-Jin
authors.initials: KJ
authors.lastname: Han
authors.forename: Joon
authors.initials: J
authors.lastname: Jo
authors.forename: Doo-Hyung
authors.initials: DH
authors.lastname: Lee
mesh_terms: D059925:Anatomic Landmarks; D000886:Anthropometry / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D015992:Body Mass Index; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging; D006801:Humans; D016014:Linear Models; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D010173:Palpation; D011237:Predictive Value of Tests; D011859:Radiography; D016059:Range of Motion, Articular; D056910:Republic of Korea; D012785:Shoulder Joint / Q000503:physiopathology*; D020069:Shoulder Pain / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging