The patterns of growth and adolescent development can provide useful data that signal specific problems or simplify differential diagnoses. The rate of stature change, the growth velocity, may be derived from the growth chart (see Chap. 7). The growth chart also has a graph that depicts percentiles of weight for attained linear stature. This information may prove useful in evaluating problems such as malabsorption syndromes or chronic illness, in which most children are relatively
underweight for height, or hypopituitarism, in which children are relatively overweight for height.

The body segment ratio (upper segment/lower segment ratio) is determined by measuring the lower segment (pubis to soles), subtracting that value from the height to calculate the upper segment (crown to pubis), and dividing the upper by the lower. These proportions change throughout development. At birth, the trunk is relatively long compared with the extremities, but by the end of puberty, the extremities are relatively longer than the trunk (Fig. 18-1). The body segment ratio at birth is ˜1.7:1; it becomes ˜1:1 by 8 to 10 years of age, reflecting the growth of long bones. Blacks are relatively long-limbed compared with whites and have upper/lower segment ratios of ˜0.90 after puberty (Fig. 18-2). Tables of normal body segment ratios and arm span measurements have been published.1