An investigation was undertaken to determine the effect of chiropractic adjustments on static radiological parameters. Standard plain film radiography was used. A retrospective consecutive case analysis approach was used for obtaining the data from the pretreatment and comparative posttreatment radiographs. Measurements for cervical lordosis, sacral base angle, lumbar lordosis, scapular angle, Cobb's angle and retrolisthesis of adjusted lumbar segments were determined by marking films in a blinded fashion. Intra- and interexaminer reliability for the measurement of cervical lordosis and retrolisthesis were determined to be excellent with a low standard error (Pearson's r range 0.89-0.97, p less than .001 for cervical lordosis and Pearson's r 0.74-0.90. p less than .001 for retrolisthesis). The data from pre- and comparative post-measurements of retrolisthesis showed a significant reduction of approximately 34%. No reduction was seen in a control group with retrolisthesis. No pre/post comparative changes were observed with cervical lordosis angle, sacral base angle, lumbar lordosis angle, scapular angle or Cobb's angle.