SUMMARY Pincer nails are a common problem, and various treatments have been reported. However, there is no simple assessment of severity. We designed a curvature index for the nail plate to assess the severity of pincer nail. Measurement of the curvature index was as follows. The apparent width of the nail tip was defined as A, and the traced length of the nail tip was defined as B. The curvatu...

Methods On the AP long film standing radiographs of 40 consecutive patients, undergoing surgery for IS, the Cobb angle (a) and the direct distance (h) between the upper end vertebra and the lower end vertebra (centroid of vertebral body) were measured. The length of the spinal curvature (c) was calculated in the computer program using the formula: c=ah/2sin/2 For each patient the calculated len...

Human spinal biomechanics are profoundly complex and not well understood, especially in terms of the dynamic spine function. Translation of biomechanics to disease is difficult, particularly since cause must be separated from effect. Primary dynamics predisposing to the onset of chronic spinal disorders, e.g., adolescent idiopathic scoliosis (AIS) or ankylosing spondylitis (AS), must clearly be...