Statural growth, a fundamental characteristic of childhood, is a complex process that is determined by the interaction of genetics, nutrition, and socioeconomic factors . Regular assessment of growth is an essential part of pediatric practice. The importance of comparing a child's growth pattern to established norms cannot be overemphasized. Because growth is an active process, growth velocity charts are more useful than are standard (distance) growth charts in determining the normality of growth . However, in interpreting a child's growth velocity, allowance must be made for age, pubertal development, and other factors.
The causes, diagnosis, and treatment of children with abnormally rapid growth and tall stature will be reviewed here. The evaluation of children with short stature is discussed elsewhere. (See "Causes of short stature" and "Diagnostic approach to children and adolescents with short stature".)
Before considering abnormal growth, one should understand normal growth and development. (See "Normal growth patterns in infants and prepubertal children", section on 'Linear growth'.)
Growth velocity — In both boys and girls, peak growth velocity occurs during the fourth month of intrauterine life, reaching 2.5 cm/week (130 cm/year) , followed by a slowing until birth. In the first year of life, linear growth remains rapid; approximately 25 cm is gained. The rate of growth declines, and the average gain is 12.5 cm/year between the first and the second year, 7 cm/year between ages two and four, 6 cm/year between ages four and six, and then 5.5 cm/year until puberty.
The second acceleration in height velocity takes place at puberty. Girls have their peak height velocity (mean 9 cm/year) during early puberty (Tanner stages II to III) (figure 1A), whereas boys reach their peak height velocity (mean, 10.3 cm/year) during mid-puberty (Tanner stages III to IV) (figure 1B) [4,5]. After the pubertal growth spurt, growth velocity diminishes toward zero as the epiphyses of the long bones fuse .