Child growth and development

We describe physical development (height, proportionality, maturity of the system...) and neurological development (gross motor, fine motor, cognitive development, speech).

average birth weight (PH): 3500 g (then 10% weight loss); doubling of PH – in the 4th-5th months; tripling of PH – in 1 year (approx. 10.5 kg);
toddlers, preschoolers and school children should have 2kg annual gain.

age	height/height	weight	head circumference
at birth	50 cm	3,5 kg (PH)	34 cm
6 months			43 cm
1 year	75 cm	10,5 kg (3×PH)	47 cm
2 years	87 cm (½ dospělé výšky)	13 kg (4×PH)
3 years	96 cm		50 cm
3,5 years	100 cm
5 years	110 cm	20 kg
10 years	140 cm	30 kg	53 cm
18 years	167,3 cm (girl), 180,2 cm (boy)^[1]		56 cm

Head/trunk ratio: newborn 1/4, adult 1/8.
proportion of muscle mass: 22% at 3 months, 35% at 3 years, 40% adult male
Power consumption:
- infant: 40% energy for growth (110 kcal/kg per day);
- toddler: 3% energy for growth (60-90 kcal/kg per day).

Periodization of child growth[edit | edit source]

The human growth pattern is referred to as„sandwich“ pattern, because between the period of rapid postnatal growth and the pubertal spurt there is a period of quiet growth (childhood; 2 to 11 years of life), unlike in other biological species.
ICP growth model according to Karlberg:
- component I (infancy), infantile component of growth - from the 2nd half of intrauterine development to the 3rd to 4th year of life; mainly IGF-I is applied;
- component C (childhood), the children's component of growth - begins before the end of the 1st year of life and lasts until the end of physical growth; dominant influence of growth hormone and persistent action of IGF-I;
- component P (puberty), pubertal component of growth – phase of additional growth induced by puberty; it accelerates until the age of the highest growth rate, it slows down until the end of growth; influence of sex hormones. ^[2]
Humans grow relatively slowly (compared to other mammals) – in most mammals, a period of rapid postnatal growth is followed by a pubertal spurt and sexual maturity. In addition, a person has a period of quiet growth between these periods - childhood (specificity of a person).

Replication of neuronsis completed before birth, but their organization continues long after birth.
White brain matter and synapses increase.
Gray matter develops relatively late – it grows from the 30th week of gestation and ends in the 1st year, therefore it is relatively sensitive to damage in late gestation and perinatally.
Myelination begins in the 4th month of gestation in the spinal cord, in the last trimester and in the brain;
- at birth, myelination of autonomic nerves, cranial nerves (except optic and olfactory) is complete
- the cortex and connections to the thalamus and BG are incompletely myelinated (here, myelination ends within 2 years).

the first stage is nonverbal
from 2 months, communication begins to be vocalized – mutual vocal play;
6-10 months - the child begins to better control the oral muscles, begins to babble and repeat syllables without a specific meaning;
at 12 months begins to have a need to use specific words to refer to objects and activities;
at 18 months can speak about 20-50 words;
attention – speech development can be delayed by frequent otitis media with conductive hearing impairment;
understanding develops faster than expressive ability;
- the child understands the first words already at 9 months;
- can understand 20-100 words at 13 months;
at the end of the 2nd year, the child begins to put words into sentences.

The basic tool for assessment is the percentile chart of body height;
- the basis for compiling percentile graphs is national reference studies;
- we thus evaluate the degree of difference from the norm;
- 94% of the population lies between the 3rd and 97th percentiles;
- medium height – between 25-75 percentile (50% of the population);
- great height – above 75th percentile;
- very high height – over 97th percentile..
The assessment includesan assessment of the child's genetic growth potential ; dítěte;
- we draw on the right edge of the percentile graph;
  - for boys – the body height of the father (point O), the body height of the mother increased by 13 cm (point M);
  - for girls – mother's body height (point M), father's height minus 13 cm (point O);
- the middle between these values is the average expected adult height, with a range of 8.5 cm;
With repeated measurements, we can calculate the growth rate in cm/year;
- it changes depending on age and gender - we evaluate it from the percentile chart.
- children from the age of two are correctly measure with a stadiometrattached to the wall - on the stadiometer scale there is a moving head that touches the vertex of the head (or have a giraffe there);
- children under two years old are measured using the so-called body meter („trough“) – we determine length.

Milk teeth
- eeruption – on the mandible 5–7 month, on the maxilla 6–8 Moon;
- exfoliation – mandible 6.–7. year, maxilla 7–8 year;
- eruption of all milk teeth should be within 3 years of life;
- we indicate a dental examination when not a single tooth has erupted within 13 months.
Permenant dentition
- lower incisor – 6.–7. year (mandibula), 7.–8. year (maxilla);
- second molar – 12.–13. year (mandibula).

LEBL, Jan – PROVAZNÍK, Kamil – HEJCMANOVÁ, Ludmila. Preklinická pediatrie. 2. edition. Galén, 2007. ISBN 978-80-7262-438-6.