Final answer:
The correct measurement for an infant's length is from the crown to the heel. This measurement is part of standard growth assessments to track an infant's healthy development.
Step-by-step explanation:
An infant's length should be measured from the crown to the heel. This method of measurement is used once the baby is born and no longer confined to the fetal position. In contrast, measurements before birth are taken from the crown to the rump. A healthy, well-nourished, full-term newborn generally measures about 51 cm (20 in.) in length at birth. During infancy, the fastest growth occurs, with a newborn usually tripling their birth weight and doubling their birth length by their first birthday. It's crucial for health providers to accurately measure a child's growth as it's a significant indicator of their overall health and development.