Postnatal Growth & Maturation. Growth & Maturation GROWTH – Increase in size of tissue or organ...
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Transcript of Postnatal Growth & Maturation. Growth & Maturation GROWTH – Increase in size of tissue or organ...
PostnatalGrowth & Maturation
Growth & Maturation
GROWTH– Increase in size of tissue or organ
Hypertrophy– Auxetic – increased cell size– Accretionary – increased extracellular constituents
Hyperplasia– Multiplicative – increased cell number
MATURATION– Change in structure or function of the tissue or organ
moving it closer towards the mature state
Methods of Studying Growth
Longitudinal Study– one or more individuals are monitored over several
years– time consuming, costly, attrition of sample– only way to study the dynamics of growth
Cross-Sectional Study– sample many different children at same time– good for norms and bench marks
Count Philibert de Montbeillard
Measured son every 6 months from birth to 18 years
(1759-1777)
Standards for Growth Assessment
What are the appropriate criteria for choice?– Cross-sectional / longitudinal– Local / National / International– Special populations
What is available?
NCHS/CDC Growth Charts
The most commonly used norms in North America are cross-sectional norms produced in 1977 by the National Center for Health Statistics.
These were recently updated and are now presented by the Center for Disease Control (2000)
CDC Growth Charts
Height for Age & Weight for Age
Weight for Height
BMI for Age
EARLYLATE
Comparison of early and a late maturers who attain similar height at age 17yrs
Longitudinal vs Crossectional
CDC Growth Charts All Racial and Ethnic Groups Combined
• Environmental influences appear to contribute to variations in growth more than genetic influences
• Inadequate sample data for racial- and ethnic-specific charts
• The effect of race and ethnicity on BMI-for- age is unclear
Anthropometric Assessment of Special Populations
A Special Population is one that can not be assessed by orthodox methodology
Growth & Nutritional Status assessments
Treatment and Rehabilitation of Treatment and Rehabilitation of Children with cerebral palsy, Children with cerebral palsy, brain injuries and other brain injuries and other neuromotor problemsneuromotor problems
S.H.A.P.E.S.
SELECTED MEASUREMENTS & EQUIPMENT
ANTHROPOMETRICMEASUREMENTS
MEASUREMENTEQUIPMENT
weight wheelchair scale or portablebeam-type balance scale
stretch stature or recumbentlength
stadiometer or recumbentboard
segment lengths - upper armand lower leg
modified segmometer
girths - head, relaxed armand calf
anthropometric metal tape
skinfolds - triceps,abdominal and medial calf
Slim Guide skinfold caliper
S.H.A.P.E.S. custom software– serial plotting (up to 100 measurement occasions)– anthropometric profile
Height Distance & Velocity Curves
Adolescent growth spurt growth most rapid in first two years
DISTANCE CURVE
VELOCITY CURVE
Height Velocity Curves
Indicator of maturity
Needs longitudinal data
Other “systems” have similar curves
Shifting of age axis values to coincident age of PHV before averaging velocity curves
Means of PHV Parameters
Age at takeoff – ♀: 8.5 - 10.3 yrs ♂: 10.3 - 12.1
yrsAge at PHV
– ♀: 11.4 - 12.2 yrs ♂: 13.4 - 14.4 yrsPHV (cm/yr)
– ♀: 7.0 - 9.1 yrs ♂: 8.2 - 10.3 yrs
Intrauterine growth velocity is greater than during any postnatal period.
Timing of birth affects growth velocities
Predicting Adult Size
Predictions of adult stature can be made from:– heights at earlier age– parental stature– skeletal maturation
Four Curves of
Growth
Differential GrowthBirth to Maturity
30-40 times– Muscle, Genital Organs
20-25 times– Body, Skeleton, Respiratory System
15-20 times– heart, Liver
< 5 times– Nervous System
Head Circumference for Age
Shape Changes with Age
Changes in Proportions
Somatotype
Sheldon vs Heath-Carter Shape vs Size Mainly used as photographic record of child
Adult Size not well correlated with Birth Size
Adult proportions are a result of complex genetic and environmental influences
Differential Growth
Mean Ages (yrs) at Peak Velocity
Girls (n=10) Boys (n=12)
Leg Length 11.3 13.4
Stature 11.8 14.1
Sitting Height 12.4 14.6
Humerus Width 11.9 14.1
Tibia Width 11.1 13.6
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Table 4-1: Indication(●) of when peak size velocity of each measurement is expected to occur in relation to Peak Height Velocity (PHV)
Before PHV
After PHV
Weight ●
Sitting Height ●
Leg Length ●
Shoulder Width ●
Elbow Width ●
Knee Width ●
Arm Girth ●
Thigh Girth ●
Adult Sexual Dimorphism
No difference in proportional weightMale-Female difference greatest in: Triceps, Biceps, Front Thigh and Medial Calf Skinfolds Secondary sexual adiposity
Adult Sexual Dimorphism
Estimates of Muscularity
Skinfold-Adjusted Arm Girth – Muscularity Indicator
G
Ga = G - (3.14xS)
S = Skinfold ThicknessG = GirthGa = Skinfold adjusted Girth
Ga
SG
Girth adjusted for Skinfold at that site
Girth Skinfold
s.a. Arm girth Relaxed Arm Girth Triceps
s.a. Chest girth Chest Subscapular
s.a. Thigh girth Thigh Front Thigh
s.a. Calf girth Calf Medial Calf
s.a. Forearm girth Maximum Forearm Forearm
s.a. Girth (cm) = Girth (cm) - (Π x Skinfold (mm) / 10)
Adult Sexual Dimorphism
s.a. Girths are Muscularity indicators
Greatest differences between the sexes in the upper body
Greatest potential for hypertrophy in the upper body
Muscularity profile is very sensitive to the specific activity of the individual
Adult Sexual Dimorphism
Proportionally larger sitting height in females
Males tend to have proportionally longer limbs.
Biggest difference in distal segments
Adult Sexual Dimorphism
Humerus to Femur Width differences reflects muscularity differences
Males have broader and deeper chests proportionally.
Classic hip-shoulder dimorphism:
Males proportionally wider shoulders
Females have proportionally wider hips
Shoulder-Hip Dimorphism
48
Sex N MeanStd.
Deviation
Biacromial/Biiliocristal Breadth Male 69 1.44 0.12
Female 115 1.31 0.12
49
2D:4D Ratio(2nd digit length to 4th digit length ratio)
Sex N Mean Std. Deviation
Male 136 0.947 0.029
Female 137 0.965 0.026
2D 4D
a Allison A. Bailey, Peter L. Hurda, Department of Psychology, University of Alberta. 2004
2D:4D Ratio
Ratio determined in utero– 2D:4D is negatively correlated with prenatal testosterone and
positively correlated with prenatal estrogen
Larger ratio in females– Married women had higher 2D:4D ratios than unmarried
women– Significant negative associations were found between 2D:4D
in men and reproductive success and significant positive relationships between 2D:4D in women and reproductive success
Found to be related to:– Aggression, Competitive success, Sexual orientation
51
Histogram of Both Sexes Combined
Sex N Mean S.D.
Male 76 0.975 0.037 Female 66 0.994 0.043
Gradient vs Indicator Maturity Gradients
– assessment of the relative rates of development of parts or structures of the body
Maturity Indicators– Some characteristic of the body that has distinct
stages of development that all normally developing children will pass through
Maturity Gradient
54Upper Arm Maturity Gradient
Three 13 year old Girls
Three 14 year old Boys
Bigness vs Maturity
Do not confuse size with maturationObesity often associated with
advanced maturation skeletally but not in muscular development
Maturity Indicators
Age of Peak Height VelocitySkeletal AgeDental AgeMenarcheSecondary Sexual Characteristics
Skeletal Age
Closer relationship of Age at Menarche with Skeletal Age (SA) than Chronological Age (CA)
Stages of Penis Development
Stages of Pubic Hair Development (Girls)
Synchrony of Pubertal Events
Synchrony of Pubertal Events
Maturity Indicator Intercorrelations