The measurement of the medial longitudinal arch in children.

Both feet of two hundred and seventy two children aged between five years six months and ten years and eleven months were studied using a footprint technique called the arch index (Al), and the vertical height of the navicular (NH) as non invasive techniques of objective measures of the medial longitudinal arch (MLA). In addition to age the study investigated the influence of gender, limb dominance, and body weight. The study found the existence of a relationship between the two measures of the MLA. There was no significant difference in NH measures between males and females and body weight did not affect the NH. The NH changed with age, suggesting it provides a useful, easily obtained clinical measure. The Al measures were slightly more reliable than the NH but showed less change with age.