The relationship of thoracic spine length and birth weight was evaluated in newborn infants of 26-41 weeks gestational age, and standards of thoracic spine length were established. Thoracic spine length is an accurate index of trunk length in the: if the gestational age is known, a markedly lengthened thoracic spine suggests that the mother is diabetic, while a markedly shortened thoracic spine suggest retarded intrauterine growth.