pedological anatomy

2. • NEONATAL SKULL
 Has got 270 bones as compared to an adult
who has 206 bones.
 Skull bones in neonate are 45(due to
incomplete ossification),adults have 22.
 Frontal bones at birth is in two halves,which
fuses at 2 years.
 There are two parietal bones.
 Occipital bone at birth consists of 4
pieces,fuses by 3-4 years of life.
 Mastoid process is asbsent in neonate,thus
stylomastoid foramen lies superficial.

3.  Mid point : mid-point of stature of a two-month-old embryo
is at chest , close to chin.
 At birth : This may shift to just above umbilicus.
 In adults : It is at pubic-symphysis region.
 Lengths of head doubles by adulthood, but rest of body
grows still more, hence at birth 22% of body area is
covered by head.
 This decreases to 13% at 12 years and only 10% in an
adult.
 There is an axis of increased growth extending from head
towards feet.
 In a newborn child height is measured using a measuring
tape in a lying down position and hence it is referred to as
LENGTH.
 Normal value of length in new born child is 45-50 cm.

4.  The newborn is usually kept in a
supine posture but can be literally
‘folded’ to its most comfortable
posture i.e., posture simulating fetal
posture of partial flexion.
 Mild lordosis and protuberance of
abdomen is a common finding at 2-3
years of age , but this disappears by
4 years.

5.  Neck is relatively short at birth and its
muscles are not developed for supporting
the head.
 Functional development of these muscles
begins from two months onwards.

6.  The girth of chest at birth is smaller than
head circumference.
 It becomes equal at 2 years and 15 years its
ratio becomes 3:2.
 Final ratio in adults is 5:3.
 The chest is rounded in newborn.
 Its final shape is attained by the time
puberty is reached.

7.  The umbilicus of a newborn is shed-off
around 12th
to 15th
day.
 The umbilicus is everted and in some
cases umbilical hernia may be
present.
 At this stage abdomen is equal to
chest until two years.
 After two years the abdominal
circumferences is less than the
chest’s.

8.  At birth: Legs are short , arms long.
 Arms : Birth to 2 years-length increases by 6.57%.
At 8 years-50% longer than at two years
By 16 to 18 years-slow growth , increases
development takes place , thus an early maturer has
shorter arms than a late maturer.
 Legs: At birth-short and curved.
Birth to 2 years-length increases 40%.A lot of fat
on medial aspect of foot gives appearance of a flat foot.
6 years-straight , knock-knee and flat foot
appearance gets corrected.
8 years-50% longer than at birth.
Adloescence-4 times longer than birth.

9.  At birth : head circumference is around
35 cm
Head shape is rounded but sometimes
it may get molded during parturition as
over-riding of parietal bone takes place
when head gets engaged in birth canal.
 Six months : increases to 44 cm.
 One year : circumference may be more
than chest circumference.
A total 4 inches increase takes place(2
inches first 4 months and then 2 inches
next 8 months)
 One year onwards : b/w 1 to 2 years 4
inches increase takes place.

10. o They bridge gap b/w bones that limit them.
o Are made up of dura mater,the primitive periosteum and
aponeurosis from inside outwards.
FONTANELLES AT BIRTH
a) Anterior fontanelles , b/w 2 parietal bones and frontal
bones.
b) Posterior fontanelle , b/w 2 parietal bones and occipital
bone.
c) Sphenoid fontanelle , b/w frontal, parietal, temporal and
sphenoid bone.
d) Mastoid fontanelle , b/w parietal , occipital and temporal
bone.

11. 1. Enables fetal skull to modify
its size and shape as it
passes through birth canal
and permits rapid growth of
brain during infancy.
2. Helps physician to gauge
degree of brain
development by their state
of closure.
3. Anterior fontanelles serves
as a landmark for
withdrawal of blood for
analysis from superior
sagital sinus.

12. • Cranial synchondroses play an important role in
craniofacial growth.
• Spenoccipital : closes by 17-20 years.
 sphenoethamoidal : closed by 2-4
years;may persists and fuse later in
adolesence,but is of little importance in
postnatal growth.
 Mid sphenoid:close shortly after birth.
• Other synchondrosis :
 Intraoccipital
 Sphenopetrosal
 Petrooccipital.

13.  At birth lower 3rd
and middle 3rd
of face are
underdeveloped due to absence of teeth.
 Forehead is high and bulging.
 Face of newly born baby is round and flat.
 Eyes dominate and owing to absence of root of
nose, appear to be widely separated.
 Child’s convex facial profile is straightened out,
owing to more anterior position of jaws.
 Development of chin prominance and deeper
position of eyes through growth of orbital ridges
and ridge of nose enhances this impression.

16. • It is comparatively large in relation to small
mouth.
• Tongue is flat, thin and blunt tipped,
probably due to short frenum.
• Tongue , at this stage performs only one
function, i.e.; acts as a piston while sucking.

17. REFLEXES PRESENT AT
BIRTH

18. INTRODUCTION
• A REFLEX is defined as an
involuntary, or automatic,
action that your body does
in response to something,
without even having to
think about it.
• Types of reflexes present
at birth:
1.General body reflexes
2.Facial reflexes
3.Oral reflexes

20. MORO REFLEXES
• Any sudden movement of the
neck initiates this reflex.
• A way of eliciting the reflex is
to pull the baby half-way to
sitting position from supine
and suddenly let head fall
back to a short distance.
• Reflex consists of rapid
abduction and extension of
arms with opening of hands.

21. CLINICAL SIGNIFICANCE

24. PALMER/ GRASP REFLEX
• When the baby’s palm
is stimulated, the hand
closes.
• There is also a
corresponding planter
reflex.
• Both normally
disappear by 24
months.

25. CLINICAL SIGNIFICANCE
• An exceptionally strong grasp reflex may
be found in the spastic form of cerebral
palsy and in kernicterus.
• It may be asymmetrical in hemiplegia and
in cases of cerebral damage.
• It should have disappeared in 2-3 months
and persistence may indicate the spastic
form of cerebral palsy.

27. ASYMMETRIC TONIC NECK
REFLEX
• When the baby is at rest and
not crying, he lies at intervals
with his head on one side, the
arm extended to the same
side, and often with a flexion of
the contra lateral knee.
• This reflex normally
disappears after 2 or 3
months, but may persist in
spastic children.

28. PARACHUTE REFLEX

29. LANDAU REFLEX
• It is seen in vertical
suspension, with the head,
spine and legs extended.
• If the head is flexed, the
hips, knees and the elbows
also flex.
• It is normally present from 3
months and is difficult to
elicit after 1 year.
• Absence of reflex occurs in
hypotonia, hypertonia or
severe mental abnormality.

30. FACIAL
REFLEX

31. NASAL REFLEX
• Stimulation of the face or nasal
cavity with water or local irritants
produce apnea in neonates.
• Breathing stops in expiration with
laryngeal closure and infants
exhibit bradycardia and lowering of
cardiac output.
• Blood flow to skin, splanchic
areas, muscles and kidney
decreases, whereas the flow to the
heart and brain is protected.

33. ORAL
REFLEXES

34. ROOTING REFLEX
• When the infant’s cheek
contacts the mother’s breast,
the baby’s mouth results in
vigorous sucking movements
resulting in baby rooting for
milk.
• When the corner of 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.

36. SUCKING

37. SWALLOWING
• Begins around 12 and
half weeks IU life.
• Full swallowing and
sucking is established by
32-36 weeks of IU life.
• Their absence in full-
term baby would suggest
a developmental defect.

38. GAG REFLEX

39. CRY

40. Conclusion
Appropriate knowledge of reflexes enables a
paedodontist
 to identify whether the child is developing
normally or not
 to identify whether development is going on
at a proper rate or not
 Knowledge of abnormalities if all reflexes
are not proper

41. REFERENCE
• SHOBHA TONDON (FOR PEDIATRICS
DENTISTRY) 2nd
EDITION.