Age range: 8 to 15 years
In general:
(1) the arm span for boys is always greater than stature.
(2) the arm span for girls is less than stature for most girls until after age 11.5 years
difference between the arm span in cm and height in cm =
= (arm span in cm) - (height in cm)
Confidence limits: 95%
line estimate for upper limit (97.5%) of difference for boys =
= (0.51 * (age in years)) - 1.93
line estimate for lower limit (2.5%) of difference for boys =
= (0.52 * (age in years)) - 4.35
line estimate for upper limit (97.5%) of difference for girls =
= (0.24 * (age in years)) - 1.97
line estimate for lower limit (2.5%) of difference for girls =
= (0.24 * (age in years)) - 3.42
If the difference is above or below the normal range for difference, then there may be a disorder causing a disproportion in body development (stunting or elongation affecting either limbs or trunk.
The technique would be limited in detecting a process that affects limb length and height to the same degree. Therefore the method needs to be done in conjunction with an assessment of height for age.
