Foot and hand length for prediction of vital capacity in scoliotic children.

Expected values of vital capacity (VC) and other lung function variables in children are usually predicted from regression equations of the index test on stature. In children with scoliosis, arm span or an "uncoiled" stature derived from the observed stature and the degree of spinal angulation have been used to predict expected values. Stature and hand and foot length were measured and all three anthropometric indices were used as independent variables for the prediction of VC in 489 normal children and adolescents (aged 4-18 years). VC was highly correlated with stature for boys and girls with regression coefficients of 0.93 and 0.91, respectively. For foot length, corresponding coefficients were 0.90 and 0.83, and for hand length 0.90 and 0.80. In 14 scoliotic children, aged 5.9-18.4 years, a close agreement was found for predictions of VC from arm span, uncoiled stature and hand and foot length. When accurate measurements of stature cannot be made, hand or foot length can be used to predict expected VC. This approach may be an alternative to the use of arm span or uncoiled stature to predict VC in children with scoliosis.