in infancy
the first year:
average newborn: 20 in. 7 1/2 lbs
most newborns are 18-22 inches long and weigh 5-10 lbs
most lose 5 to 7% if body weight (adjusting)
physical development gender and ethnic differences
•males slightly larger
•females more resilient and physically mature
•african americans ahead of hispanic americans who are ahead
of europeans americans in physical development
head to body proportions
•at 2-3 months prenatally 1/2 of total body
•at birth - 1/4 of total body
•by age 2 - 1/5 of total body
•adult - 1/8 total body
patterns of growth:
1. cephalocaudal pattern: development sequence in which the
earliest growth always occurs at the top--the head
•physical growth and differentiation of features gradually work
their way down from top to bottom
2. proximodistal pattern: sequence in which growth starts at the
center of the body and moves toward the extremities
the brain:
•at birth - 25% of its adult brain weight
•by age 2-70 to 75%...
•between 3 and 6-90%
•adolescence - 95%