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      The child is not a miniature adult. The period of development into a
fully integrated human being, which begins with the embryo, does not cease
until mental and emotional as well as physical growth is complete. In the
physical sense, development does not merely mean that the various parts of
the child grow larger but also that these parts change, adapting to some
extent according to the demands of the environment.
      For the physical therapist, involved in treating children with any
disorder interfering with normal development, it is important to understand
not only what function develops at a particular chronological age but also
how the baby prepares himself for each new step in his development. It is
not so important in treatment to know, for example that a baby can usually
sit without support from his hands by the eighth month but it is important to
know why he can do this. He has developed this ability because he has good
head control and sufficient extension against gravity and has developed
effective balance in this position. It is important to know that until he can sit
like this, he will not be free to use his hands; therefore manipulation will not
progress at a normal speed and learning will be retarded.
      Growth and development are a continuous dynamic process, which
occurs from conception to maturity and follows certain sequences. They are
the key concepts for understanding the behavior and needs of the child.

Principles of development:
1. Development is a continuous process from conception to maturity. It must
be thought of in terms of mere milestones. Before any milestone is reached,
the child has to go through many preceding stages of development, which
are very important for developmental diagnosis. Diagnosis does not contain
so much of observing what a child does but how he does it. For example, in
case of a seven-month child, one has to observe not whether he can sit but
how he sits and with what degree of maturity he does it.

2. Development depends on the maturation and myelination of the nervous
system. Until that has occurred, no amount of practice can make the child
learn the relevant skill. When practice is denied, the ability to perform the
skill lies dormant, but the skill is rapidly learnt as soon as opportunity is
given. Myelination of the nervous system begins by the fourth fetal month
and is evident first in the anterior and posterior spinal roots:
* At birth, all the cranial nerves, except the optic and olfactory nerves are
myelinated. The autonomic nervous system is mature. Some of the spinal
nerves are mature, fully myelinated and functional. The sensory receptors
for pressure, pain and temperature are also mature. On the other hand, the
brain stem, some of the finer configurations of the cortex and projection
fibers are immature and probably incompletely myelinated.
* By two years, all structures at the spinal cord, brain stem and cerebellum
are myelinated.
* By three years, peripheral nerve roots are myelinated.
* By five years, myelination of all cerebral structures seems to be complete.

3. The sequence of development is the same for all children but the rate of
development varies from child to another. For example, the child has to
learn how to sit before he can walk but the age at which children learn how
to sit and walk varies considerably.

4. Certain primitive reflexes anticipate corresponding voluntary movement.
These reflexes have to be lost before voluntary movement develops. For
example, grasp reflex and walking reflex of the newborn period should be
lost before manipulation and locomotion starts.

5. The direction of development is cephalo-caudal. Development in the
extremities develops in a proximo-distal direction. Control of the arms and
legs occurs before control of the wrists, fingers, feet and toes. The first step
in the development of locomotion is the acquisition of head control,
involving the neck muscles. Later, the spinal muscles develop coordination
so that the child is able to sit up with a straight back. Moreover, he can
crawl, pulling himself forward with his arms, the legs trailing behind, before
he can creep; a movement which involves the use of legs.

6. Generalized mass activity gives way to specific individual responses.
Pleasure is shown in the young baby by massive general response such as
widening of eyes, increased respiration, kicking of legs and vigorous
movement of arms. The older child or adult shows his pleasure simply by
facial expression or by appropriate words. The aimless movements of the
arms and legs of the neonate are replaced by the specific movements of the
arms (manipulation) and legs (locomotion).

                            Normal course of development

       Growth refers to change in size, resulting from the multiplication of
cells or the enlargement of the existing ones, while Development signifies
maturation of organs and systems and acquisition of skills.

Stages of growth and development:
                   Stage                                 From … To
Embryonic or fetal                                 From conception to birth
Neo-born (neonatal)                                From birth to 2 - 4 weeks
Infancy                                          From 2 – 4 weeks to one year
Toddler                                             From 1 year to 3 years
Early childhood                                        From 3 to 5 years
Middle childhood                                       From 6 to 8 years
Late childhood                                        From 9 to 11 years
Puberty and early adolescence                        From 12 to 14 years
Middle and late adolescence                          From 15 to 18 years

Normal growth parameters:
- Weight:
              Time                                    Weight
At birth                                              3: 3.5 kg
During the first 4 months                200 gm / week or 3/4 kg / month
At 5 months                                   Double the birth weight
During the second 4 months               100 gm / week or 1/2 kg / month
During the third 4 months                70 gm / week or 1/4 kg / month
By 1 year                                      Triple the birth weight
At 2 years                                   Four times the birth weight

- Height:
              Time                                Height
At birth                                 44 - 53 cm (average 50 cm)
By 1 year                                          75 cm
At 2 years                                         85 cm
At 3 years                                         93 cm
At 4 years                          100 cm (Double the birth height)

- Head circumference:
              Time                          Head circumference
At birth                                           35 cm
At 6 months                                        43 cm
At 1 year                                          47 cm
At 2 years                                         49 cm
At 4 years                                         50 cm
At puberty                                         52 cm

- Fontanels:
              Time                                 Area
At birth                         Anterior (3 fingers) – Posterior (Closed)
At 6 months                                      2 fingers
At 1 year                                         1 finger
At 1 1/2 years                                    Closed

- Chest:
       In the newborn, the chest circumference is equal to the skull
circumference and it is smaller in the premature baby. Thereafter, the chest
grows at a faster rate.

- Dentition:
       This is also liable to a wide range of variation. Teething in the lower
jaw usually precedes that of the upper jaw by 1 to 2 months.

1) Primary or deciduous teeth:
               Teeth                                Age
Central incisors                                5 – 7 months
Lateral incisors                                7 – 9 months
Canines                                        16 – 20 months
First molars                                   11 – 16 months
Second molars                                  20 – 30 months

2) Secondary or permanent teeth:
               Teeth                                Age
Central incisors                                 6 – 7 years
Lateral incisors                                6 – 11 years
Canines                                         9 - 12 years
First pre-molars                                10 - 13 years
Second pre-molars                               11 - 13 years
First molar                                      6 – 7 years
Second molar                                    12 - 13 years
Third molar                                     17 - 20 years

- Osseous development (Bone age):
       The centers of the small bones and the epiphysis and processes of the
long bones begin to show calcification in a characteristic sequence and at a
predictable age. One can usually evaluate osseous development (bone age)
for clinical purpose from X-raying certain parts of the body. Normally the

bone age should correlate with the chronological age (the age in years and
months). Any divergence between these two ages in either direction should
be considered pathological e.g. In cretinism, there is retardation of bone age,
while in adreno-genital syndrome there is advancement of bone age.

How to evaluate bone age:
* In the newborn and infancy, the ossific centers around the knee joint are
well-developed. Absence of these indicates a delay in bone age.
* In early childhood, one can evaluate the osseous development from recent
age-gram of the hand and wrist. Roughly, between 2 - 6 years there is one
carpal center per year.
* In late childhood and adolescence, evaluation of bone age is more
complicated and usually fusion of various epiphyses is considered.

- Some special aspects of development:
         Period            HR / min               BP                RR / min
Newborn                      130                80/60                  55
6 months                     120                80/60                  40
1 year                       120                80/60                  35
4 years                      100                85/65                  25
10 years                      90                100/65                 20
Puberty                       85                100/70                 20

          The heart is relatively larger in the child, being more rounded and
horizontal. The apex beat in the infant is in the 4th inter-costal space lateral
to the nipple line. After the 4th year, it is in the 5th space in or medial to the
nipple line. Radiologically, the cardiothoracic ratio is about 0.6 (compared to
0.5 in the adult).

- Neurological and behavioral development:
      It is obvious that maturation of the nervous system precedes from
above downwards, so that the normal child:
* Can hold the head erect during the 3rd month.
* Attempts to grasp objects during the 4th month.
* Can sit at 6 – 8 months.
* Try to stand at about 10 months.
* Can walk between 10 – 15 months.
* Climbs stairs at 18 months.
* Rides tricycles, goes upstairs at 3 – 4 years.

      The mental and behavioral development of the child follows a regular
pattern. The average time for attainment of various accomplishments is:
* 1 – 2 weeks: Follows light and fixes objects with eyes.
* 1 month: Pays attention to voices and music.
* 2 months: Smiles, ocular accommodation develops.
* 3 months: First exploratory activity; sucks fingers.
* 4 months: Laughs; turns head to voice.
* 5 – 6 months: Recognizes objects (bottle) and persons (parents).
* 8 – 10 months: Says mono-syllables (dada, mama).
* 1 year: Says 1 - 3 words, makes line marks with pencil on a paper.
* 2 years: Uses all words and sentences, points to eyes and nose and cry by
night if waken up.
* 3 – 4 years: Repeats sentences and attends to toilet without help.

Variations in human growth and development:
      It must be stressed that the rate of growth of healthy normal children
varies to a great extent from child to another. Some children are short and
stocky while others are tall and allowance must be made for this. In other
words, each child has his own inherent pattern of growth, with a wide
margin of variation among children. Realizing this important fact, in order to
assess the growth of any child, one has to consult the growth curves, which
demonstrate clearly the wide limits which normally normal children of the
same age-group may show.

Growth curves:
      The 3 standards commonly used for assessment of growth during
childhood are the weight, length (height) and skull circumference. The
growth curves are constructed for these 3 measurements. Taking the weight
growth curve as an example, the percentile curves are commonly used,
where the weight is plotted against the age for random samples of normal
healthy children. The 50th percentile level represents the average weight for
this age and means that the weight of 50 % of normal children falls below
this level. If the weight of a child falls at 25 th percentile, this means that his
weight is below the average but still within the normal range and so on. If
the weight falls below the 3rd percentile, or above the 75th percentile, this
means that the child is below or above the normal, respectively.
      Serial recordings of the growth measurements rather than single
record are more indicative of the child state of physical growth. A normal
growing child will persistently follow his percentile level, whether above or
below the average level and deviation from this level should be looked at
with concern.

Characteristics of the neo-born:
He/she should:
1) Be delivered at or near term.
2) Be free of congenital defects or obstetrical damage.
3) Breathes spontaneously and cries lustily soon after birth.
4) Be having a heart rate between 100 and 140 beats / minute.
5) Rapidly develops an overall healthy pink color.

General factors, affecting the course of development:
1. Intelligence:
      Intelligence is partly due to inherited (genetic) factors and partly due
to environmental factors.
Intelligence quotient (IQ) = Mental age (Verbal and performance scales) /
Chronological age x 100.
      Mentally abnormal child is retained in all fields of development,
except occasionally in gross motor skills (sitting and walking) and rarely in
sphincter control. The highly intelligent child is advanced in many fields of
development. He has high degree of responsiveness, alertness and
interaction with his surroundings. He is often advanced in the development
of speech.

2. Familial and genetic factors:
      Intelligence is determined largely by genetic factors. The familial
factor is often prominent in individual fields of development. In some
families, the development of locomotion, speech or sphincter control may be
unusually early or unusually late, while in all other fields of development
being average.

3. Personality (Independence – Confidence – Desire):
       It has a considerable bearing on the age, at which the child learns
various skills. Some babies are more independent than others, therefore they
practice new skills earlier (feeding themselves or attending their toilet
needs). Lack of self-confidence retards activities such as walking. Some
children have greater desire than others to speak. So, the age at which speech
is acquired, is influenced by such desire (acquisition of speech is affected by
the desire to speak).

4. Environment:
       Development depends on maturation of the nervous system. Training
or practice cannot accelerate it until the nervous system is ready. However,
the acceleration is then only slight. On the other hand, development can be
retarded by lack of practice when the nervous system is ready for a particular
skill. Development is also retarded by emotional deprivation such as
separation from the mother and those children who are brought up from
infancy in institutions.
       Minor degrees of emotional deprivation              and restriction of
opportunities to learn commonly occur in the home. Full-time employment
of the mother may lead to neglect of children, when they most need their
mothers. One of the manifestations of severe child abuse is retarded physical
and mental development. Some mothers keep their children off their feet for
fear that they will develop knock-knees or bow-legs. Moreover, they prevent
them from sitting for fear that the spine will be weakened. It is inevitable
that a child, who is never given a chance to learn certain skill, will be late in
learning this skill.

5. Sex:
      Generally, girls tend to learn to walk, speak and acquire sphincter
control earlier than boys do.

6. Order of birth:
      It is reported that the oldest and youngest children tend to be more
intelligent than the intermediate ones. Spacing of births in different social
classes will affect IQ of children. The larger and more closely spaced the
family, the lower the IQ than when there is a larger interval between births.

7. Handicaps:
      Development is affected by a handicap such as cerebral palsy,
deafness, meningomyelocele or any chronic illness.

8. Deterioration of performance:
      Numerous conditions may cause a slowing down in development or
even deterioration. They include malnutrition in infancy, severe emotional
deprivation and other adverse socioeconomic environmental factors, severe
personality disorders, metabolic diseases (including hypothyroidism and
hypoglycemia and degenerative diseases of the nervous system).

9. Infections:
      A mild infection in an infant such as septic umbilicus or coryza will
prevent weight gain. Acute infection produces only a temporary retardation
of growth, usually compensated by a spurt of growth in convalescence
(catch up process), often associated with a temporary increase in appetite.
Chronic infections, on the other hand, have a retarding effect on growth.

10. Endocrine glands:
      These glands have a considerable effect on growth. The following
hormones are connected directly or indirectly with physical growth; sex
hormones, anterior lobe of the pituitary, thyroid gland, parathyroid gland and


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