French angles: a simple aid to neurodevelopmental examination.

"French angles" are the amplitude of passive movement at a single joint, which can be easily measured using a goniometer, and reflect the lengthening capacity of muscles--a component of passive tone. Fifty infants aged 1-52 weeks had their "French angles" measured by non-expert examiners using a plastic goniometer. All the angles measured, except ankle dorsiflexion, increased in a predictable, linear fashion from birth to one year of age. Thus in normal term infants passive tone gradually relaxes from birth to the age of one year. Three additional infants with known neuromuscular disorders were found to have angles outside the obtained normal range. The babies with cerebral palsy had reduced adductor angles reflecting adductor spasm, and the baby with Werdnig Hoffman syndrome had an increased adductor angle reflecting increased adductor extensibility. The results provide a quantitative measurement of neurological maturation during infancy, and should complement the routine neurodevelopmental assessment. The method proved quick, simple and reliable, and may become useful as a screening test for neuromuscular disorders.