Determination of anterior displacement of the anus in newborn infants and children.

Anterior displacement of the anus is a common cause of constipation in infancy and early childhood. However, normal values are not available for defining anal displacement. Using a simple technique, an anal position index of less than 0.34 in girls and less than 0.46 in boys was indicative of anterior displacement. The diagnosis can be made in the neonatal period.