RESUMEN
OBJECTIVE: The purposes of this study were to examine the range of thoracic spine extension motion in a group of young, asymptomatic subjects and compare the radiologically derived measurements with those obtained using photographic analysis, and to examine the relationship between the magnitude of the neutral thoracic kyphosis and the range of thoracic spine extension motion. METHODS: In 14 asymptomatic male subjects (mean age ± SD, 30.2 ± 7 years), the thoracic kyphosis in standing and full thoracic spine extension was measured from lateral thoracic spine radiographs and digital photographs. The difference between the 2 measurements was used to define the range of thoracic extension motion. RESULTS: The range of thoracic extension motion measured radiologically was between 0 and 26° (mean ± SD, 12.0° ± 8.9°), whereas the photographic range was between 8° and 23° (mean ± SD, 12.4° ± 4.1°). There was a significant correlation between the photographic and radiographic measurements of extension range (r = 0.69, P < .01). Extension range of motion measured radiologically was significantly correlated with the magnitude of the thoracic kyphosis (r = 0.71, P < .01). CONCLUSION: Functional radiographs of the thoracic spine can be used to measure the extension range of motion and define the extreme of range. The range of thoracic extension motion may be influenced by the magnitude of the neutral kyphosis. This technique may be used in future studies to evaluate the impact of spinal disorders on thoracic spine mobility.