The relationship between jaw deformity and scoliosis

Objectives To analyze the relationship between lateral displacement of the mandible and scoliosis. Methods From April 2002 through July 2003, we examined posteroanterior cephalometric radiographs and chest X-rays from 85 patients with jaw deformities and a control group of 20 patients with no jaw deformities. To measure the lateral shift of the mandible, we drew a horizontal baseline (X axis) on the cephalogram connecting the intersection of the external margins of the orbits and the most lateral points of the greater wings of the sphenoid. A vertical baseline (Y axis) was then marked perpendicular to the X axis, intersecting the ethmoid crista galli. Then, we measured the lateral displacement of the mandibular mentum from the Y axis. Displacement to the right was designated positive; that to the left was designated negative. Cobb's method was used to measure scoliosis curves on chest X-rays; the direction of the curve was designated similarly. Results Of the 85 patients with jaw deformity, 23 (27.1%) had a Cobb angle exceeding 10°. None of the control group had scoliosis exceeding 10°. No correlation was found between the direction of mandibular displacement and the direction of scoliosis. Conclusion This study suggests a relationship between jaw deformities and scoliosis, as scoliosis was found in 27.1% of the patients with a main complaint of jaw deformity.