Children in elementary grades typically show slow but steady gain in height and weight. Body proportions change less than during infancy and early child hood period. The cephalocaudal and proximodistal principles of growth and development continue to operate. The lower parts of the body and the extremities fill out in this period. The child takes on more adult like body proportions. The bones continue to grow and harden and the muscles become stronger.
Height: The annual increase in height during late childhood is 2-3 inches or 5-6 cms. At the onset of puberty, an average girl of 11 years should have height of 58”i.e 139.2cms & the average boy of same age is 57.5” i.e. 138.3cms. Girls reach 90 percent of the adult height where as boys reach 80 percent by age 11.
Weight: The annual increase in weight during school age is 3-5 pounds. At the onset of puberty, an average girl of 12 years should weigh 29-30 kgs & the average boy of same age 28.5 – 29 kgs. Girls will reach half of her adult weight.
Body proportions:
Head and face: The most outstanding physical change is the changing proportion of child’s head to his body. The child’s head attains 91 percent of its adult size. The surface area of head accounts for 13 percent of the total body where as for adults it is 8 percent. The disproportion of a large head decreases & the lower part of the face increases in size, thus eliminating some of the facial disproportions of Early Childhood period. The gradual eruption of permanent teeth changes the shape of the mouth. During the transition from baby teeth to permanent teeth, deformity may also occur, if 2 jaws do not fit together affecting the shape of the face. This condition is known as Occlusion.
The trunk: It elongates & becomes slimmer, chest broadens & flattens, and neck becomes longer thus permitting shoulders to drop. The shoulders become square and broaden and become flat. Both boys and girls have greater trunk growth but boys tend to have longer legs, arms and standing height during school age period. Girls have greater hip width and thigh sizes.
Many structures in the body such as skeleton, muscles, liver, spleen kidney and face follow normal growth curve. Others like skull, reproductive organs, lymphoid tissues, intestines, subcutaneous fat do not follow the normal growth curve during late childhood.
Skeletal and muscular growth:
Girls are maturationally ahead of boys throughout late childhood. At birth girls are 4 weeks ahead of boys in skeletal age. By 12 years they are almost 2 years ahead.
Skeletal growth:
Skeletal age is estimated by the percent of cartilage that has been replaced by bone. Children’s bones have proportionately more water and less protein like material than those of adults. The blood supply to these growing structures is greater in this period.
The ligaments are less firmly attached with large spaces between bones and joints. These characteristics make the child more susceptible to bone infections carried by the blood stream, less resistant to extreme pressures and muscle pull and more flexible than adults.
Peak Bone mass: It is the highest density of bone that a person has in life. During school age and adolescence, skeleton growth is peak in its size and density.
More deposits of bone mass occur due to proper diet and exercise. Boys tend to have greater bone mass than girls. Calcium deficiencies reduce bone mass and physical activity will improve the bone mass. Determination of skeletal maturity is predicted based on the appearance of ossification.
Osteoporosis: A disease that involves a serious loss of bone density, leaving bones at risk for fractures in later life. Much of the bone tissue will be disappeared and become fragile. Girls are much more at risk for developing osteoporosis than boys.
The school age children should have adequate calcium to ensure optimal bone mass and participate in weight bearing exercises like walking, running, skating, jumping etc to promote bone health.
Muscular growth:
There is a rapid growth in muscles. The muscle fibers grow in length and breadth and are accompanied by changes in composition. The heart muscles grow more slowly in this period.
Teeth: The baby teeth are replaced by permanent adult teeth which are usually 28 of the 32 permanent teeth by the onset of puberty. The last 4 wisdom teeth erupt during adolescence. These teeth erupt earlier for girls than boys. Strong and healthy teeth in children enable them to chew properly, speak clearly and gives shape to face.
Dental caries: It is a common dental problem during school age. Regular dental health check-ups will help in maintaining good oral health during this period.
Brain Development:
Like other physical growth, brain growth during school age is slow and steady. Between 2 1/2 to 10 years the brain grows only 15 percent and reaches 90 percent of its adult brain weight. The cerebral cortex continues to grow and neural extensions, circuits and connections between neural branches become more stabilized. The brain becomes more selective in its pruning process of eliminating underused neural networks particularly in visual cortex. This may account for increasing eye hand coordination in children.
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