Infants – Physical Development

Child Development

Infants

Skeletal Growth

Skeletal System is made of bones and teeth. Skeletal growth refers to the changes in length, weight and the appearance of teeth.

Average Length: 20 to 21 inches

Most infants reach 1 ½ times their birth lengths (adding 9 to 10 inches) during the first year.

Weight

Babies usually double their birth weights in four or five months and triple their birth weights by one year.

So…

• If a baby’s beginning weight is 8 pounds, they will weigh approximately______lbs. at 4-5 months and _______lbs. at age 1!!!

By about 9 months, the infant becomes chubbier. This change happens because fat tissues under the skin have increased.

After this time, fat tissues begin to decrease. Even at this age – boys have more muscle length and thickness, while girls have more fat.

Age in Months

Length in Inches

Weight in Pounds

Birth 20 7 ½

3 23 ¾ 12 ½

6 26 16 ¾

9 28 20

12 29 ½ 22 ¼

Average Length and Weight During First Year

What happens if a baby doesn’t grow at a similar rate?

Failure to Thrive

• Rates of growth slow considerably over time.

• This may indicate that a health problem exists.

Causes of Failure to Thrive

• Diseases that prevent all or some nutrients from being absorbed or that cause nutrients to be quickly expelled from the body.

• The baby’s food is not providing enough nutrients – (diluted formula or breast milk affected by

mother’s malnutrition)

Causes of Failure to Thrive

• Feedings are offered too infrequently or last too short a time.

• The baby is abused or neglected

Body Proportions• Infants do not look like small adults.

Head makes up ¼ of his or her total length

1/10

Bones and Teeth

• Infant skeleton is mostly made up of cartilage.

• Infants bones do not break easily

• Skeletons are not sturdy = no sitting and standing

• Because of softness, bones can easily misshapen.

• Lying flat in one position all the time can flatten a baby’s head in one place.

More common because of the recommendation for babies to sleep on their backs (Prevents SIDS)

Changing a baby’s position during waking hours can prevent their heads from flattening.

Many doctors now recommend “tummy time” once babies can hold their heads up while alert. (two-four months)

“Tummy Time”

• Encourages development of motor skills such as:– Rolling over– Reaching– Crawling

Bones = Changes occur in 3 Stages during 1st Year!

1. Length of bones increases

2. Ossification begins (hardening of bones)

3. Number of bones changes • Hand and Wrist = 1 y.o = 3 bones• Hand and Wrist = adult = 28 bones

Teeth!

Hand out Sheet

By birth, all deciduous teeth (nonpermanent) teeth and a few permanent teeth are developing deep in the jaw

• Most babies begin cutting teeth during the second half of the first year. (6-12 months)

Motor Development

• The use and control of muscles that direct body movements.

Motor Development

• Learning to use and control large muscles helps babies learn to crawl and walk.– Trunk– Arms– Legs

Motor Development

• Being able to control small muscles– Hands– Fingers