normal range of thoracic kyphosis in 13 to 18 years old healthy schoolboys in kermanshah (2008)

background: increased thoracic kyphosis more than normal ranges are assessed as abnormal. but normal ranges of thoracic kyphosis in deferent age groups have not been identified in our country yet. the aim of present study was investigation of normal ranges of thoracic kyphosis to use as a diagnosis tool in school aged children in kermanshah, western-iran. methods: a descriptive research designed and ethical approval was obtained. 582 student boys 13 - 18 years old were cluster sampled randomly from two guidance and two high schools. each age group included 97 students.  dorsal curves were measured using flexicurve method. normal range of boy student’s kyphosis was determined using descriptive statistics of mean and two standard deviations. results: the mean thoracic kyphosis values ranged from 18.29 to 52.50 degrees. it was 34.41 ± 7.47 for age 13 and 35.55 ± 7.07 degree for age 18.  it increased gradually from 13 to 16 and then there was a little decrease to 18 years. conclusion: our results showed a little difference with other similar studies, which may be related to different measurement methods or personal characteristics. these can be used as normal values for local schools and these normal values need to be determined for all age groups in different population.