The body length of an infant can be estimated from the length of its long bones. This estimate should be correlated with other data such as radiographic evaluation of ossification centers.


Note: Additional measures of fetal size and development are available in the chapter on Obstetrics and Gynecology.


estimated length of infant in cm =

= ((length of humerus in cm) * 7.52) + 2.47

= ((length of ulna in cm) * 8.20) + 2.38

= ((length of femur in cm) * 6.44) + 4.51

= ((length of tibia in cm) * 7.24) + 4.90



• The estimates assume normal bone development. Underestimates may occur in fetal growth retardation or if there are bone deformities present.


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