Development Across The Life Span
INFANT
BIOLOGIC DEVELOPMENT
Proportion Changes
Growth is very rapid during the first year, especially the initial 6 months
WEIGHT
Infants gain 150 to 200 g (5 to 7oz) weekly until approximately age 5 to 6 months – when the birth weight has at least doubled
Average weight for a 6-month old child is 7.26 kg (16lb)
Weight gain slows during the second 6 months
By one year of age the infant’s birth weight has tripled, for an average weight of 9.75 kg (21.5kg)
HEIGHT
Height increases by 2.5 cm (1 inch) a month during first 6 months – slows during second 6 months
Increase in length occurs in sudden spurts, rather than slow gradual pattern
Average height is 65 cm (25 ½ inches) at 6 months and 74 cm (29 inches) at 12 months.
By one year the birth length has increased by almost 50% - occurring mainly in trunk – contributing to infant’s characteristic physique.
HEAD
Growth is rapid – circumference increases approximately 1.5 cm (3/5 inch) a month x 1st 6 months – decreases to 0.5 cm (1/5 inch next 6 months’)
By 1 year head has increased by 33%
Cranial sutures and posterior fontanel close by 6 – 8 wks. of age.
Anterior fontanel closes by 12 – 18 months of age (average being 14 months)
BRAIN
Expanding head size reflects growth and differentiation of the nervous system
By end of first year the brain has increased in weigh about 2 ½ times.
Brain maturation is exhibited in the dramatic developmental achievements of infancy. Primitive reflexes are replaced by voluntary, purposeful movement and new reflexes that influence motor development appear.
CHEST
Assumes a more adult contour – lateral diameter becomes larger than the anteroposterior diameter.
Chest circumference approximately equals the head circumference by end of first year
Heart grows less rapidly than rest of body. Weight is doubled by end of first year. Heart width is 55%of chest width.
Maturation of Systems
RESPIRATORY - Respiration slows and
BIOLOGIC DEVELOPMENT
Proportion Changes
Growth is very rapid during the first year, especially the initial 6 months
WEIGHT
Infants gain 150 to 200 g (5 to 7oz) weekly until approximately age 5 to 6 months – when the birth weight has at least doubled
Average weight for a 6-month old child is 7.26 kg (16lb)
Weight gain slows during the second 6 months
By one year of age the infant’s birth weight has tripled, for an average weight of 9.75 kg (21.5kg)
HEIGHT
Height increases by 2.5 cm (1 inch) a month during first 6 months – slows during second 6 months
Increase in length occurs in sudden spurts, rather than slow gradual pattern
Average height is 65 cm (25 ½ inches) at 6 months and 74 cm (29 inches) at 12 months.
By one year the birth length has increased by almost 50% - occurring mainly in trunk – contributing to infant’s characteristic physique.
HEAD
Growth is rapid – circumference increases approximately 1.5 cm (3/5 inch) a month x 1st 6 months – decreases to 0.5 cm (1/5 inch next 6 months’)
By 1 year head has increased by 33%
Cranial sutures and posterior fontanel close by 6 – 8 wks. of age.
Anterior fontanel closes by 12 – 18 months of age (average being 14 months)
BRAIN
Expanding head size reflects growth and differentiation of the nervous system
By end of first year the brain has increased in weigh about 2 ½ times.
Brain maturation is exhibited in the dramatic developmental achievements of infancy. Primitive reflexes are replaced by voluntary, purposeful movement and new reflexes that influence motor development appear.
CHEST
Assumes a more adult contour – lateral diameter becomes larger than the anteroposterior diameter.
Chest circumference approximately equals the head circumference by end of first year
Heart grows less rapidly than rest of body. Weight is doubled by end of first year. Heart width is 55%of chest width.
Maturation of Systems
RESPIRATORY - Respiration slows and