title: Incidence of the inability to flex the proximal interphalangeal joint in normal subjects.
abstract: OBJECTIVE
  To evaluate the incidence of the inability to flex the proximal interphalangeal (PIP) joints in normal subjects and to find clinically useful patterns of symmetry between hands. SUBJECTS, DESIGN, AND SETTING: Two hundred consecutive patients (122 women, 78 men) from a musculoskeletal clinic and inpatient rehabilitation service without history of hand or forearm injury underwent finger flexion testing.
  
  
  RESULTS
  Forty-eight percent were able to independently flex all of their PIP joints. Thirty-three percent could not do so in both fifth digits, and 19% could not do so on either the left or the right hand alone. Four subjects could not independently flex their fourth PIP joints. Nineteen percent of subjects showed asymmetry between hands.
  
  
  CONCLUSIONS
  These findings suggest that the finger flexor test should be interpreted with caution when evaluating the fifth finger PIP joint flexion. Symmetry patterns are of doubtful usefulness in predicting the function of the injured hand on the basis of the function of the uninjured hand.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Indiana University Medical Center, Fort Wayne, USA.
authors.forename: D C
authors.initials: DC
authors.lastname: Wilcox
authors.forename: R
authors.initials: R
authors.lastname: Buschbacher
authors.forename: J
authors.initials: J
authors.lastname: Bergeron
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005384:Finger Joint / Q000502:physiology*; D006230:Hand Injuries / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016059:Range of Motion, Articular