Pedologic Anatomy with special emphasis on it's applied aspect is a basic science seminar which is important to all Pediatric Dentists and BDS students both.

1. Pedologic Anatomy with special
emphasis on its
Applied Aspects
Presented by:- Dr Nivedita Jain
PG Ist Year
1

2. CONTENTS
 Definition of Growth & Development
 Introduction
 Prenatal growth changes
 Factors affecting fetal growth
 General Postnatal changes in Dimensions and Proportions
• Neonatal Skeleton
• Weight, Length and Height
• Head Circumference
• Body Proportions
• Posture
• Neck
2

3. •Chest
•Abdomen
•Extremities
Change in Craniofacial Complex
Oral features at Birth
• General Body reflex
• Facial Reflex
• Oral Reflex
Significance of Pedologic Anatomy in Pedodontics
Reference
3

4. 4 Definition of Growth
It is defined as the physiochemical process of living matter by which
an organism becomes larger. It is largely an anatomic phenomenon.
Krogman defined growth simply as increase in size, change in
proportion and progressive complexity.
Profitt (1986) further simplified and explained growth as an increase
in size or number.

5. 5 Definition of Development:-
It is a physiological and behavioural phenomenon
comprising of changes and complexity in functions.
According to Toss (1931) : Development is defined as
progress towards maturity.
Whereas; Moyers (1988) stated that development consists
of all the naturally occurring unidirectional changes in the
life of an individual from its existence as a single cell to its
elaboration as a multifunctional unit terminating in death.

6. INTRODUCTION
 A child may appear as a miniature adult but the details of the
anatomy reveal that a child is entirely different from an adult.
 We need to understand normal growth, development,
anatomy and behaviour in order to monitor child's progress,
to identify delays or abnormalities in development, and to
counsel parents.
6

7. Foetal Growth Changes7

8. End of Fourth Week (First Month)
 Length of the foetus is around 4mm and begins to curve in c-shape
 Buccopharyngeal membrane ruptures.
 The development of face with the formation of upper lip and nostrils take
place. Palate is incompletely formed.
 The cerebral hemispheres appear as hollow buds
 The eyelids are present in the shape of folds above and below the eye.
8

9. Enamel organs are developed from dental lamina.
The limbs now appear as oval flattened projections
Kidney begin to form with tubules. Heart forms, starts functioning and
body system begin to form.
The backbone and vertebral canal form small buds that will develop
inner and upper extremities.
Heart forms, start functioning and body systems begin to form.
9

10. 10

11. END OF SECOND MONTH
 Eyes are far apart with eyelids fused and nose is flat.
 Ossification of bones begins and limbs become
distinct as the upper and lower extremities.
 By the beginning of the fifth week, forelimbs and
hindlimbs appear as paddle-shaped buds
 Formation of digits start appearing by formation of
four radial grooves which are known as rays.
11

12. Major blood vessels form.
Many internal organs continue to develop.
 By the end of the second month the foetus measures from 28 to 30 mm.
in length
 Counting somites becomes difficult during the second month of
development, the age of the embryo is then indicated as the crown-rump
length (CRL) and expressed in millimetres.
 CRL is the measurement from the vertex of the skull to the midpoint
between the apices of the buttocks
12

13. 13 CLINICAL CORRELATIONS

14. END OF THIRD MONTH
 The face becomes more human
looking
 Bridge of nose develops and external
ears are formed.
 Ossification begins and continues
 The head flexion increases & the neck
becomes proportionately larger.
 Length of the foetus is about 7 cm,
but if the legs be included it is upto 9
to 10 cm.
14

15. The umbilical protrusion of the gut is reduced with proportionate
abdominal volume.
Heart beat is detectable.
External genitalia develop to such a degree that the sex of the foetus can
be determined by external examination (ultrasound).
 The eyes, initially directed laterally, move to the ventral aspect of the
face, and the ears come to lie close to their definitive position at the
side of the head .
 The limbs reach their relative length in comparison with the rest of the
body, although the lower limbs are still a little shorter and less well
developed than the upper extremities.
15

16. END OF FOURTH MONTH
 Face takes on human features and hair appears on the head.
 Bones are ossified and joints begin to form with continued development of the
body system.
 Condyle, coronoid and angle of mandible become distinct.
 The external ear is formed on the side of the head and is no longer in upper part
of the neck.
 The length of the foetus is from 12 to 13 cm.
 Skin is bright pink.
16

17. 17

18. END OF FIFTH
MONTH  Rapid development of body systems take place.
 Skin is bright pink and sebaceous glands
become active forming “Vernix Caseosa” on
skin.
 foetal movement called “Quickening” can be
seen.
 Total length of the foetus, including the legs, is
from 25 to 27 cm.
18

19. END OF SIXTH MONTH
 Head becomes smaller but is still disproportionate to the rest of the body.
 Eyelids separate and eyelashes form.
 Skin is wrinkled and pink because of lack of underlying connective tissue.
 Increase in the growth of the cutaneous and subcutaneous tissue occurs.
 Ameloblast and odontoblast are formed.
19

20. END OF SEVENTH
MONTH
 Head and body become more
proportionate.
 Skin still is wrinkled and pink.
 Eyebrow hair and eyelashes are
developed.
 The pupillary membrane atrophies and
the eyelids are open.
 From vertex to heels the total length at
the end of the seventh month is from 35
to 36 cm.
 The weight is a 1000-1300 gm.
20

21. END OF EIGHT MONTH
 Subcutaneous fat deposition take place.
 The foetus present is of Plump appearance
 The skin assumes a pink colour
 Testes descend into scrotum.
 There is progressive loss of lanugo except for the hair on eyelids, eyebrow and
scalp.
 The umbilicus is gradually centrally located.
 The total length, i. e., from head to heels, is about 40 cm
 Chances of survival are much greater by this period.
21

22. END OF NINTH
MONTH
 Additional subcutaneous fat accumulates.
 Skull has the largest circumference of all the
parts of the body
 Lanugo sheds.
 Nails extend to the tips of the fingers and even
beyond.
 The umbilicus is almost in the middle of the
body
 Length is 45-50cm
 Weight is 2.5-4.5kg
22

23. MONTHS CROWN-RUMP
LENGTH(cm)
WEIGHT(gm)
3 5-8 10-45
4 9-14 60-200
5 15-19 250-450
6 20-23 500-820
7 24-27 900-1300
8 28-30 1400-2100
9 31-34 2200-2900
24

24. Developmental horizons
during foetal life
HORIZONS EVENT AGE (WEEKS)
 Taste buds appear 7
 Swallowing 10
 Respiratory Movements 14-16
 Sucking Movements 24
 Some sounds can be heard 24-26
 Eyes sensitive to light 28
25

25. CLINICAL CO RELATION
Low Birth Weight
 Intrauterine growth restriction (IUGR) is a term applied to infants who are at or
below the 10th percentile for their expected birth weight at a given gestational age.
Sometimes these infants are described as small for dates, small for gestational age
(SGA), foetally malnourished, or dysmature.
 Approximately 1 in 10 babies have IUGR and therefore an increased risk of
neurological deficiencies, congenital malformations, meconium aspiration,
hypoglycaemia, hypocalcaemia, and respiratory distress syndrome (RDS).
 The incidence is higher in blacks than in whites.
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26. FACTORS AFFECTING FOETAL GROWTH
Genetic Potential
 The potential traits are usually transmitted to offspring.
 The size of head is more closely related to parents than are the size and
shape of hand and feet
 Structure of chest and fatty tissue has better genetic association than other
somatic characteristics.
27

27. Foetal Hormones
 Human foetus secretes thyroxin from 12th weeks of gestation period
 Thyroxin and insulin have a role in regulation of tissue acceleration and
differentiation
 Glucocorticoid influence the pre partum maturational events of organs such
as liver, lungs and gastrointestinal tract.
 Growth hormones are present in high level but does not affect the foetal
growth.
28

28. Placental factors:
 Foetal weight is directly correlated to placental weight
 Foetal growth is highly dependent on structural and functional integrity of
placenta.
 The total villus surface area increases , diffusion distance decreases,
capillaries dilate and the resistance to feto-placental vasculature falls.
 The positive remodelling facilitates the enhanced nutrient transport across
the placenta.
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29. Maternal factors
 Mother’s diet, nutrient intake and body composition plays an important
 Maternal use of tobacco, cigarettes, drugs, alcohol retards foetal growth.
 Obstetric complications such as pregnancy induced hypertension, pre-
eclampsia, and multiple pregnancy produce foetal growth restriction.
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30. LAWS OF GROWTH
 Growth and development of children is a continuous and orderly process.
 The foetus grows fast in the first half of gestation, therefore rate of growth is
slowed down until the baby is born
 In early postnatal period velocity of growth is high specially in first few months,
thereafter slower but steady growth during mid childhood
 Second phase of accelerated growth occurs at puberty.
 Growth de-accelerates thereafter for sometime and finally ceases.
32

31. Different tissues of body grow at
different rates
 General body growth
 Brain growth
 Growth of gonads
 Lymphoid growth
33

32. Postnatal Growth
A postpartum (or postnatal) period begins immediately
after the birth of a child as the mother's body, including
hormone levels and uterus size, returns to a non-pregnant
state. The terms puerperium or puerperal period, or
immediate postpartum period are commonly used to refer
to the first 6 weeks following childbirth.
34

33. GENERAL POST NATAL DIMENSIONS AND
PROPORTIONS
Neonate Skeleton
 The neonate has 270 bones as compared to an adult who has 206 bones.
 Skull bones in the neonate are 45 (due to incomplete ossification) & in the adult
22.
 Frontal bone is in two halves separated by metopic suture and fuses by 2 years
 Two Parietal bone are present
35

34.  Occipital bone has four parts, one squamous, two condylar, and one
basilar which fuses by 4 years of life .
 Each temporal bone has four parts which completely fuses by puberty
 Mastoid process is absent in neonates thus stylomastoid foramen lies
superficially.
36

35. Body Proportions
 The body proportions are a result of a differential rates of growth of
the cephalic and caudal ends.
Mid point
 the mid point of a 2 month old child is at the chest, while in an adult
it is at the pubic symphysis region.
 At birth- just above umbilicus.
 The length of the head doubles by adulthood.
 There is an axis of increased growth extending from heads towards
the feet. This is called as cephalo caudal gradient.
37

36. 38

37. 39

38. Normal Growth Values
 The infant measures 50cm at birth
 60cm at three months,
 70cm at 9 months,
 75cm at one year
 A normal Indian child is 100cm tall at age of 4 ½ years
 Gains about 6cm in height every year, until age of 12years
 Target height :
o boys (cm) = father’s ht. + mother’s ht. + 6.5
2
o Girls (cm) = father’s ht. + mother’s ht - 6.5
2
40

39.  1cm/month for next three months
 Half cm/month for next 6 months
 By one year of age, circumference is 45-47cm
 Between one to two year 4 inches increase takes place.
 At 10 years
 95%of the total head growth completes with the width of the
head completed by 3 years while the length of the head
completes by 17 to 18 years.
 It increases 2cm/month for first three months.
41

40. Posture
The new born is usually kept in supine position but can be literally folded in its
most comfortable posture ,i.e. the posture simulating the foetal posture of partial
flexion, mild lordosis and protuberance of abdomen are common finding at 2-3
years of age but disappears by 4 years.
Neck
Neck is relatively short at birth and its muscles are not developed at birth for
supporting the head. Development of these muscle begin from 2 months onwards.
43

41. Chest
 Chest circumference is measured at level of nipples,
mid way between inspiration and expiration.
 At birth the chest is smaller than the head
circumference. It becomes equal at 2 years and by 15
years its ratio becomes 3:2.
 The final ratio in adults is 5:3.
 The chest is rounded in new born and final shape is
attained by the time of puberty.
44

42. Abdomen
 The umbilicus of the new born sheds off
around the 12th to 15th day after birth.
 The umbilicus is everted and in some cases
umbilical hernia may be present.
 Circumference of the abdomen is equal to
the chest until 2 years.
 After two years it is less than chest.
45

43. Extremities
At birth:- legs are short and arms are long.
Arms:-
 To measure the mid arm circumference first mark a point midway between
tip of the acromian process of scapula and olecranon of ulna, while the
child hold the left arm by his side.
 birth to 2 years – length increases by 6.75%.
 At 8 years - 50% longer than at 2 years.
 By 16 to 18 years - slow growth, increased development takes place
 Thus an early mature baby has shorter legs than a late matured baby.
46

44. 47

45. Legs
 At birth-short and curved.
 Birth to 2 years- length increases 40%.
A lot of fat on the mesial aspect of the foot gives the appearance of a
flat foot.
 6 years:- straight, the knock knee and flat foot appearance gets
corrected.
 8 years-50 % longer than at 2 years.
 Adolescence- 4 times longer than at birth.
 Early maturer- shorter legs than the late maturer.
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46. Weight
 The weight of the child in nude or
minimal clothing is recorded accurately
on a lever or electronic type of weighing
scale
 The weighing scale should have a
minimum unit of 100gm.
49

47. Length
 Length is recorded under the age of two
years.
 Child is placed on a rigid measuring table or
an infantometer in a supine position
 Length of baby is measured from a scale,
which is set in the measuring table.
50

48. Standing Height
 For the standing height child stands upright,
heels separated and weight even on both
feet
 Head is so positioned that the child looks
directly forwards with the Frankfurt’s
horizontal plane and biauricular plane being
horizontal.
51

49. Head Circumference
 Measurement is done using a non stretchable tape
the maximum circumference of the head from the
occipital protuberance to the supraorbital ridges on the
forehead is recorded.
 The head circumference is about 35 cm at birth.
 Head shape is rounded but sometimes it may get
moulded during parturition as over riding of the
parietal bone takes place when the head gets engaged
in birth canal.
52

50. Changes in Craniofacial Complex
The skeletal portion of the craniofacial complex develops as a blend of morphogenesis
of primary skull components.
1. Neurocranium consists of
 2. Viscerocranium is formed by the bones of facial skeleton which develop
by intramembranous ossification. This is derived from the branchial arches.
54
Desmocranium
Chondrocranium

51. Dimensional Changes in Craniofacial Structures
 These changes can be appreciated even in Intra Uterine Life.
 The entire cranium becomes longer and wider in its relation to height.
 At birth:- Head makes up about a greater part of total body length
whereas in adult it accounts for about one eighth of the total body
height. While the size of the cerebral cranium will increase by about 50%,
the facial skeleton will grow to more than twice the original size.
55

52. By 4 years:-
 Cranial circumference thus increases from about 33cm (at birth) to 50 cm at
3 years after which it only increases by 6 cm.
4th year onwards:-
 Facial skeleton increase in all dimensions during the post natal growth
period, the increase in height being the greatest (approx. 200%).
 In depth the increase is somewhat smaller(approx 75%).
 Increase in width is the smallest(approx 15%).
56

53. Fontanelles
They bridge the gap between the bones that limit them. They are made up of the
duramater, the primitive periosteum and the aponeurosis from inside outwards.
57
(18 to 24 months after birth)
(2 months after birth)
(3 months after birth)
(Begins to close 1 to 2 months after birth, closed
completely by 12 months)

54. Clinical importance of fontanelles
1. Enables the foetal skull to modify its size and shape as it passes through the
birth canal and permits rapid growth of the brain during infancy.
2. Helps the physician to gauge the degree of brain development by their state
of closure.
3. Anterior fontanelle serves as a landmark for withdrawal of blood for analysis
from the superior sagittal sinus.
4. Depressed level of fontanelle indicates dehydration and increased level
indicates an increased intracranial pressure.
58

55. 59
Encephalitis
 Hydrocephalus
 Meningitis
Fontanels
Bulging
Down syndrome
Premature birth
Congenital rubella
Fontanels
enlarged
• Due to malnutritionShrunken

56. Craniofacial Synchondroses
It plays an important role in craniofacial development.
 Sphenoccipital: closes by 17-20 years.
 Sphenoethmoidal :closed by 2-4 years; may persist and fuse later in adolescence, but is of little
importance in postnatal growth.
 Mid sphenoidal: closes shortly after birth.
 Other synchondroses:
 1.Intraoccipital
 2.Sphenopetrosal
 3.Petrooccipital
 Craniotabes or soft skull due to paper thin bones is palpable in premature infants.
61

57. Sutures of Cranium
62
Closes at 24 years to 35 years
(Closes 22 years to 30 years)
(Closes at 29 Years)

58. Clinical Co Relation
 The shape of the skull depends on which of the sutures closed prematurely.
 Early closure of the sagittal suture (57% of cases) results in frontal and
occipital expansion, and the skull becomes long and narrow (scaphocephaly)
 Premature closure of the coronal suture results in a short, high skull,
known as acrocephaly, or tower skull
63

59. 64
 If the coronal and lambdoid sutures close prematurely on one side only,
asymmetric craniosynostosis, known as plagiocephaly.
 In some cases the cranial vault fails to form (cranioschisis), and brain
tissue exposed to amniotic fluid degenerates, resulting in anencephaly.
 Children with relatively small defects in the skull through which meninges
and/or brain tissue herniate (cranial meningocele and
meningoencephalocele, respectively)

60. Face
1. At birth, the lower 3rd and middle 3rd of the face are underdeveloped due to
absence of teeth.
2. The forehead is high and bulging.
3. The eyes dominate and owing to the absence of the root of the nose, appear
to be widely separated.
4. After the onset of puberty the forehead flattens and widens, lips thicken and
face acquires an oval shape, mainly due to growth of the jaws
65

61. 66

62. Nasomaxillary Complex
 The maxilla develops in the membranous tissue at the end of sixth foetal week.
 The maxilla is attached to the neurocranium directly with the fronto maxillary
sutures and indirectly by means of various other facial structures such as the
nasal, lacrimal and ethmoidal bones, nasal septum including vomer, palatine
bone and zygomatic bone. These structures are joined in edge to edge
relation.
 During early phase interrelation between jaws are characterised by mandibular
protrusion, which gradually reversed.
67

63. 68  At birth the maxilla is placed more anteriorly giving class II relationship of
the jaws.
 Later on both maxilla and mandible with their associated soft tissue grows
forward and downward & establish a normal class 1 relationship.
 Maxillary sinuses are not well developed and are present like slits.
 Development of orbital cavities complete at birth.
 The alveolar process can only be faintly discerned and palate has weak
transversal curvature.
 The maxillary body is almost entirely filled with the developing teeth.

64. 69

65. 72

66. Clinical Co relation
Facial clefts-
a. Cleft lip and palate
b. Median cleft lip
c. Oblique facial clefts
73
Teratogens are likely to cause lip defects if the embryo is exposed to them
during 5th & 6th weeks.
The palate is more susceptible between 7th and 8th week.

67. Mandible
 At birth, the two rami are short and condylar development is minimal.
 A thin line of fibrocartilage and connective tissue exists at the midline of the
symphysis to separate the right and left mandibular bodies. This symphyseal
cartilage is replaced by bone (between 4 months of age and end of 1stYear)
 The alveolar processes and the muscles are poorly developed at this age, so
that its basal arch mainly determines the shape of the mandible in the
neonate.
 At birth the structure of mandible is shell like with the 10 alveolar sockets for
the developing tooth germs.
74

68.  During the 1st year of life, appositional growth is specially active at
alveolar border, at the distal and superior surface of ramus, condyle
and lower border of mandible along with lateral surfaces
 After the 1st year , resorption occurs along the anterior border of
ramus lengthening the alveolar border
 Transverse dimensions, after 1 year are mainly due to the growth at
posterior border in an expanding “V” pattern.
 The two rami diverge outwards from below to above so that additive
growth at the coronoid notch, coronoid process and condyle also
increases the superior inter ramus dimensions.
75

69.  The position of mandibular foramen changes by remodeling, to a more
superior position from occlusal plane as child matures.
 The foramen is below the occlusal plane in a very young child, slightly at the
occlusal plane during the period of primary dentition .
 It averages 7mm above the occlusal plane in the adult.
 Angle of mandible is more obtuse in young children.
 Mental foramen is placed very close to border of mandible in young children
 Forward shift of growing mandibular body changes direction of mental
foramen during infancy & childhood.
76

70. 77

71. 78

72. 79 Inferior Alveolar Nerve Block
Clinical implication-

73. 80 Mental Nerve
 In infants and children, the syringe needle may be applied at right
angles to the body of the mandible to enter the mental foramen
 In the adult, the needle must be applied obliquely from behind to
achieve entry

74. Temporomandibular Joint
Three phases of development are seen in the intrauterine life period.
1.Blastemic stage:- (7 to 8 weeks of development) corresponds with the
organisation of the condyle, articular disc and capsule.
2.Cavitation stage:- (9 to 11 weeks of development) corresponds to the initial
formation Of inferior joint cavity and then start of condylar chondrogenesis.
3.Maturation stage:- (after 12 weeks of development)
81

75. Postnatal Changes in TMJ
1. At birth the articular disc is flat and develops an accentuated S-shaped
profile as the articular tubercle develops.
2. Condylar cartilage is approximately 1.5 mm thick at birth, but soon
thins down to about 0.5 mm, by 20 to 30 years of life it is completely
replaced by endochondral ossification.
3. Mandibular condyle grows in a constant posterior, superior and lateral
direction and attains a mature contour by late mixed dentition period.
82

76. 83
Oral features of Neonate
Upper Gum Pad
Gingival Groove Dental Groove
Lateral
Sulcus

77. Lower Gum Pad84

78. Relationship of Gum Pads
 There is no definite anteroposterior relationship of the gum pads on occlusion, but the lower gum
pad being smaller, the lateral sulcus of the lower gum pads lies distal to that of the upper.
 Variable overjet with contact only in the first molar segments.
 During function the mandibular movements at this stage are mainly vertical and to a very small
extent in the anteroposterior direction. Lateral movements are absent.
 During the early phases of foetal development the sagittal interrelationship of the jaws is
characterized by a mandibular protrusion ,which is gradually reversed.
 At birth the lower jaw is often situated posteriorly .this relationship has some clinical significance as
disturbed postnatal forward growth of the mandible may result in Malocclusion.
85

79. 86

80. Growth of Gum Pads
 At birth the width of the gum pads are inadequate to
accommodate all the incisors
 The growth of the gum pads is rapid in the first year after
birth.
 Growth is more in transverse direction and in the labiolingual
direction.
 Due to growth the segments of each gum pads become
prominent.
87

81. Tongue
 It is comparatively large in relation to the small mouth.
 Tongue is flat, thin and blunt tipped.
 The tongue at this stage performs only one function i.e. acts
as piston while sucking.
 It is formed from 3 swellings, i.e. lingual swelling, tuberculum
impar and hypobrachial eminence.
88

82. Buccal Pad of Fat
 It is also called as corpus adiposum or bichat”s fat pad.
 It is child’s reserve of energy, it is nothing but the cheek
prominence giving the infant a chubby cheek appearance. It is
formed of a thin encapsulated mass of fat lying between the
subcutaneous fat and the muscles of cheek.
 Exact role in suckling is not known but it regress as suckling
ceases.
89

83. External Features of a Newly Born Child
Skin
• Colour:- Often reddish
• May have an appearance of cyanosis
• Mongolian Spots
• Vernix Caseosa
• Premature infant has deep red skin with fine, soft, immature lanugo hair.
• Post term infants may show a whitish, peeling, parchment like skin.
• Erythema toxicum
• Pustular melanosis is a similar, benign vesiculo popular rash at birth in some
blacks, around the chin, back, extremities, palms and soles.
90

84. 91
Eyes
Size Cornea Lens
Fundus Retina

85. 92
Nose
 Small and flat with narrow nostrils.
 Bridge of the nose is depressed. Maximal growth of the nasal
cartilage occurs till puberty, after which it attains it’s final form.
 Hair within nose become thicker around puberty.
Lips
 Lips of a new born are reddish pink, soft and supple.
 The midline of the upper lip has a small projection, the labial tubercle
(sucking callus) which is said to disappear after the cessation of
suckling.
 Abrupt separation of the mucosa covering the inner aspect of the lips
from the outer aspect by a thin single line, parallel to the free border of
lip.
 Undergo a slow transformation to form the transition zone between
the outer and inner aspects after one year.

86. What is reflex?
Definition:-
It is an involuntary, or autonomic , action that the body does in
response to something , without even having to think about it. The
reflexes can be broadly studied under 3 categories:-
1.General body reflex
2.Facial reflex
3.Oral reflex
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87. Reflexes present at Birth
i. Moro reflex
ii. Startle reflex
iii. Grasp / Palmar reflex
iv. Walking / Stepping reflex
v. Limb placement reflex
vi. Asymmetric tonic neck reflex
vii. Babinski’s reflex
viii.Parachute reflex
ix. Landau reflex
x. Tendon reflex
xi. Abdominal reflex
95

88. i. Moro Reflex
 Any sudden movement of the neck initiates this reflex.
 A satisfactory way of eliciting the reflex is to pull the baby
half way of eliciting the reflex is to pull the baby half way
to a sitting position from the supine and suddenly let the
head fall back to a short distance.
 The reflex consists of a rapid abduction and extension of
the arms with the opening of hands. Arms then come
together as in an embrace.
 The Moro reflex is present at birth, peaks in the first
month of life, and begins to disappear around 2-3 months
of age
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89. Clinical Importance
 It’s nature gives an indication of muscle tone.
 The response may be asymmetrical if muscle tone in unequal on the two
sides, or if there is weakness of an arm or any injury to the humerus or
clavicle.
 Bilateral absence of the reflex may be linked to damage to the
infant's central nervous system, while a unilateral absence could mean an
injury due to birth trauma.
 In human evolutionary history, the Moro reflex may have helped infants
cling to the mother while being carried around.
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90. ii. Startle Reflex
 Similar to Moro reflex but it is initiated by a sudden noise
or any other stimulus.
 The elbows are flexed and the hands remain closed, there
is less of embrace, outward and inward movement of the
arms.
 By the time your baby is 3 to 6 months old, they probably
won't demonstrate the strartle reflex any longer.
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91. iii. Palmar/ Grasp reflex
 When the baby’s palm is stimulated, hands closes.
 There is also a corresponding PLANTAR reflex.
 Normally disappears by 24 months.
Clinical Significance
 An exceptionally strong grasp reflex may be found in the spastic form of
cerebral palsy and in kernectirus.
 It may be asymmetrical in hemiplegia and in cases of cerebral damage. It should
have disappear in in 2 or 3 months and persistence may indicate the spastic
form of cerebral palsy.
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92. iv. Walking/ Stepping reflex
When the sole of the foot is pressed against the couch, the baby
tries to walk. It persists as voluntary standing.
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93. v. Limb Placement Reflex
When the front of the leg below the knee, or the arm below the elbow is
brought into contact with the edge of the table, the child lifts the limbs
over the edge.
Clinical significance-
Reflex is readily demonstrable in newborn and persistent failure to elicit it
at this stage is thought to indicate neurological abnormality.
This reflex disappears by 6 weeks due to increased ratio of leg weight to
strength.
It reappears by 8 month to 1 year when the child starts to walk.
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94. vi. Asymmetric tonic neck reflex
102
 When the baby is at rest and not crying, he lies at intervals with his head on one
side, the arms extended to the same side and often with the flexion of the
opposite knee.
 Also called as ‘fencing posture' .
 This reflex is present at one month of age and disappears at around four months
, but may persist in spastic children.
 If the infant is unable to move out of this position or the reflex continues to be
triggered past six months of age, the child may have a disorder of the upper
motor neurons. According to researchers, the tonic neck reflex is a precursor to
the hand/eye coordination of the infant. It also prepares the infant for voluntary
reaching.

95. vii. Babinski’s reflex
 The Babinski reflex occurs after the sole of the foot has been firmly
stroked. The big toe then moves upward or toward the top surface of
the foot. The other toes fan out.
 It is named after the Russian neurologist Boris Petrovitch Babkin.
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96. viii. Parachute Reflex
 It appears at about 6-9 months and persists thereafter. The reflex is
elicited by holding the child in ventral suspension and suddenly
lowering him to the couch. The arms extend as defensive reaction.
 In children with cerebral palsy, the reflex may be absent or abnormal.
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97. ix. Landau reflex
 It is seen in vertical suspension, with the head, spine and legs
extended.
 If the head is reflexed, the hips, knees and the elbows also
flex.
 It is normally present from 3 months and is difficult to elicit
after 1 year.
 It is poor in those with floppy infant syndrome and
exaggerated in hypertonic and opisthotonic infants.
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98. x. Tendon reflex106
 They are present in neonate.
 They are of great value for the diagnosis of cerebral palsy.
 In spastic children the tendon jerk are exaggerated.
 The pectoralis major was the most readily elicitable reflex in all
infants(100%), regardless of maturity.

99. xi. Abdominal Reflex
They are also present in most of the new born babies. In these reflex
there contraction of the muscles of the abdominal wall on stimulation
of the skin or tapping on neighboring bony structures.
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100. 108
Nasal reflex
Stimulation of the face or nasal cavity with water or local irritants produces
apnea in neonates. Breathing stops in expiration with laryngeal closure and
infants exhibit bradycardia and lowering of cardiac output.
Blink reflex
Various stimuli provoke blinking.
Whether the child is awake or asleep, pupils of the eyes react to changes in
the intensity of light.
Facial Reflex

101. 109
Corneal reflex
Consists of blinking when the Cornea is touched.
When the stimulus ,whether sound, light, or touch, has been received .
The reflex occurs at a rapid rate of 0.1 seconds.
Pupil reflex
The pupils react to light, but in the preterm baby and some full term babies the
duration of exposure to light may have to be prolonged to elicit the reflex. The
light should not be bright, for a bright light will cause closure of the eyes.
Doll’s Eye Reflex
Normal response in newborns to keep the eyes stationary as the head is moved to
the right or left.
The reflex disappears as ocular fixation develops.
During the first week they are able to maintain these fixations against passive

102. Oral Reflexes
Consists of the following types of reflexes:110
Rooting
Reflex
Suckling
Reflex
Swallowin
g
Gag
Reflex
Masticatio
n

103. i. Rooting Reflex
 When the infants cheek contacts the mother's breast, the baby's mouth results in
vigorous sucking movements resulting in the baby rooting for milk.
 When the corner of the mouth is touched, the lower lip is lowered, the tongue moves
towards the point stimulated. when the finger slides away, the head turns to follow it.
 When the centre of Upper lip is stimulated, the lip elevates.
Onset: 28 weeks IU
Well established: 32-34 weeks IU
Disappears: 3-4 months
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104. ii. Suckling Reflex
 Onset – 28 weeks IU
 Well established:32 to 34 weeks IU
 Disappears: starting around 12 months
 Elicited by: the sucking reflex is tested by introducing a finger or teat into the
mouth, when vigorous sucking will occur.
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105. iii. Swallowing
Begins around 12.5 weeks of IU life.
Full swallowing and sucking is established by 32-36 weeks of IU life.
 Infantile swallow
Until the primary molars erupt, infant swallow with the jaws separated and the
tongue thrust forward using facial muscles(orbicularis oris and the
buccinator).This is a non conditional congenital reflex.
 Acquired congenital reflex
After eruption of the posterior primary teeth, from 18 months of age onwards,
the child tends to swallow with the teeth brought together by the masticatory
muscle action, without a tongue thrust.
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106. 114
Cry reflex
 It is a un conditioned reflex which accounts for its lack of
individual character and is of sporadic nature.
 It starts as early as 21-29 weeks intrauterine.

107. Significance of Pedologic
Anatomy in Pedodontics
 Knowledge of pedologic anatomy is very helpful for a pedodontist. It not only
serves as an adjunct in diagnosis but also helps in treatment planning
 The knowledge of the development of motor skills and language similarly also
helps a pedodontist to gauge whether the development is going on at a proper
rate or not
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108.  The anatomical post natal development also aids in a similar way.
 The knowledge of various growth spurts helps in planning treatment
specially in interceptive orthodontic cases, where growth has to be
modified or wherever surgery is involved e.g. in cleft cases, functional jaw
orthopaedics.
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109. References
 Tandon S, Introduction to pedodontics, In: Text book of pedodontics, 2nd
edition, hyderabad paras medical publisher, 2008, pg 50-63.
 Inderbir Singh, Alimentary System, In: Human Embryology, 8th edition,
Macmillan Publishers, 2010, pg 126- 166.
 S G Damle, Growth and Development. In:Textbook of Pediatric
Dentistry, 5th Edition, Arya Medi Publishing House, 2017, pg 304-328
 S I Bhalajhi, Growth and Development, General Principles and
Concepts, In Textbook of Orthodontics, 5th Edition, Arya Medi
Publishing House, 2013, pg 9-49
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110. Frequently Asked Questions
1. Growth Spurts
2. Scammon’s Curve
3. Gum Pads
4. Reflexes present at birth
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111. 119

112. Pupillary Membrane
Persistent pupillary membrane (PPM) is a condition of the eye
involving remnants of a fetal membrane that persist as strands
of tissue crossing the pupil. The pupillary membrane in
mammals exists in the fetus as a source of blood supply for the
lens.
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113. Meconium
It is the dark green substance forming the first faeces of a
newborn infant.
Meconium aspiration syndrome (MAS) also known as neonatal
aspiration of meconium is a medical condition affecting newborn
infants. It describes the spectrum of disorders and
pathophysiology of newborns born in meconium-stained amniotic
fluid (MSAF) and have meconium within their lungs.
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114. Amniotic Fluid
During pregnancy, your growing baby is cushioned inside a fluid-filled
bag (amniotic sac) in your womb (uterus).
Amniotic fluid protects the developing baby by cushioning against blows
to the mother's abdomen, allowing for easier fetal movement and
promoting muscular/skeletal development. Amniotic fluid swallowed by
the fetus helps in the formation of the gastrointestinal tract.
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115. 123
Delayed growth puts the baby at risk of certain health problems during pregnancy, delivery, and after birth.
They include:
•Low birth weight
•Difficulty handling the stresses of vaginal delivery
•Decreased oxygen levels
•Hypoglycemia (low blood sugar)
•Low resistance to infection
•Low Apgar scores (a test given immediately after birth to evaluate the newborn's physical condition and
determine need for special medical care)
•Trouble maintaining body temperature
•Abnormally high red blood cell count
In the most severe cases, IUGR can lead to stillbirth. It can also cause long-term growth problems.
Causes of Intrauterine Growth Restriction
IUGR has many possible causes. A common cause is a problem with the placenta. The placenta is the tissue that
joins the mother and fetus, carrying oxygen and nutrients to the baby and permitting the release of waste
products from the baby.
Intra Uterine Growth Restriction

116. 124
The condition can also occur as the result of certain health problems in the mother, such as:
•Advanced diabetes
•High blood pressure or heart disease
•Infections such as rubella, cytomegalovirus, toxoplasmosis, and syphilis
•Kidney disease or lung disease
•Malnutrition or anemia
•Sickle cell anemia
•Smoking, drinking alcohol, or abusing drugs
Other possible fetal causes include chromosomal defects in the baby or multiple gestation
(twins, triplets, or more).
IUGR Symptoms
The main symptom of IUGR is a small for gestational age baby. Specifically, the baby's
estimated weight is below the 10th percentile -- or less than that of 90% of babies of the same
gestational age.
Depending on the cause of IUGR, the baby may be small all over or look malnourished. They
may be thin and pale and have loose, dry skin. The umbilical cord is often thin and dull instead
of thick and shiny.
Not all babies that are born small have IUGR.

117. 125
Indian Population
India with 1.21 billion people constitutes as the second most
populous country in the world, while children
represents 39% of total population of the country. The figures
show that the larger number of about 29 percent constitutes
Children in the age between 0-5 years.

118. 126
Orbit

119. 127

120. 128