Growth is an extraordinarily complex process governed by multiple factors: genetic, epigenetic, environmental, and psychosocial. As such, growth in children integrates the genetic and environmental influences at the level of individual cells, organs, and the organism as a whole, providing a window into the functioning of any organism, in particular children. Growth is the bellwether of health, and its evaluation is the cornerstone of pediatrics. Children who grow normally must have all the genetic and environmental requisites for growth in place. Those who do not should be looked at carefully to discover the cause, whether it is genetic, environmental, or a systemic disease, either endocrine or nonendocrine.
Like any variable, the correct measurement of growth is essential and not without its challenges. An inappropriately measured height can lead to unnecessary investigations, can prove costly, and can be anxiety-inducing for the child and family. Although mistakes can be made measuring a child’s weight, and weight may vary between different scales in different clinics, weight measurement is much less prone to error than that of height. For that reason, the discussion will focus mostly on height.
The Frankfurt plane is a concept that should be known by any practitioner measuring height. The Frankfurt plane is used in craniometry to define a standard head position. The concept was developed during the World Congress on Anthropology held in Frankfurt, Germany, in 1884. The plane by definition passes through the upper margins of the external auditory meatus, a point called the porion, and through the lower margin of the left bony orbit, a point called the orbitale. These points are defined on the bony skull. In practice, endocrinologists define the Frankfurt plane as the plane that passes through the tragion (the notch above the tragus of the ear) and the orbitale. The Frankfurt plane should be parallel to the floor when measuring height and to the foot plate when measuring supine length.
Children 2 years and younger should be measured in a supine position using a Harpenden infant measuring table (Fig. 515-1). Ideally, 2 individuals should be doing the measurement. The vertex of the skull should be in contact with the stationary head plate, and the head position should be such that the Frankfurt plane is perpendicular to the table or parallel to the mobile foot plate. The child should be placed supine on the table, with 1 person holding the head in contact with the head plate. The other person should be holding the legs in line with the body, with the knee fully extended and the heels in contact with the foot plate. This is easily achieved by holding both ankles with 1 hand, stretching the legs, and moving the foot plate in contact with the heels using the other hand. ...