neonate

1. Presented by:
Piyush Verma
MDS 2nd yr
Deptof Paedodontics & Preventive Dentistry

2. Contents
⚫Introduction
⚫Ref lexarc
⚫Classificationof reflexes
⚫Significanceof reflexes
⚫Types of ref lexes
⚫Conclusion

3. Introduction
⚫A reflex is an involuntaryorautomaticaction thatyour
body does in response to something without even
having to think about it
⚫Neonatal reflexes – inborn reflexes presentat birth &
occurin a predictable fashion
⚫Normallydeveloping newborn should respond to
certain stimuli with thesereflexes

4. Reflex arc
⚫Anatomical pathway fora ref lex is
called as reflex arc
⚫It has 5 components :
 Receptor
 Afferent nerve
 Center
 Efferent nerve
 Effectororgan

5. Classification of reflexes
⚫Depending upon whetherinborn oracquired
 Unconditioned reflexes, inborn reflex
 Conditioned reflexes/acquired reflexes

6. ⚫Depending upon the situationof thecenter
 Cerebellar reflexes
 Cortical reflex
 Midbrain reflex
 Bulbaror medullary ref lexes
 Spinal reflexes

7. ⚫Depending upon the purpose
 Protective/flexorreflexes
 Antigravity/extensorref lexes
 Depending uponclinical basis
 Superficial reflexes
 Mucus membrane
 Cutaneous reflex
 Deepreflexes
 Visceral reflexes
 Pathological reflexes

8. Significance of reflexes
⚫Helpsa paedodontist to identify whetherthechild is
developing normallyor not
⚫Tellsaboutwhatabnormalities thechild may be
having if all reflexes are notproper
⚫Knowledge of development of motor skills – helps to
identify whether development is going on at a proper
rateor not

9. Types of reflexes

10. General body reflexes :
 Moro ref lex/Startle ref lex
 Palmar/grasp reflex
 Plantargrasp ref lex
 Walking/stepping reflex
 Limb placement reflex
 Asymmetrictonic neck reflex
 Symmetric tonic neck reflex
 Babinski’s reflex
 Babkin reflex
 Parachutereflex
 Landau reflex

11.  Withdrawal reflex
 Trunk incurvation reflex
 Tendon reflexes
 Gallant’sreflex
Tonic labyrinthinereflex
Facial reflexes :
 Nasal reflex
 Blink reflex
 Doll’s eye reflex
 Auditoryorienting ref lex

12. Oral reflexes :
 Rooting reflex
 Sucking reflex
 Swallowing reflex
 Gag reflex
 Cry ref lex

13. General body reflexes
⚫Mororef lex/ startle ref lex
 Beginsat 28 weeks of gestation
 Initiated by any sudden movementof
the neck
 Elicited by -- pulling the baby halfway
to sitting position from supine &
suddenly let the head fall back
 Consistsof rapid abduction & extension
of arms with the opening of hands,
tensing of the back muscles, flexion of
the legsand crying

14. Within moments, thearms come together again
⚫Clinical significance
Its nature gives an indication of muscle tone
Failureof the arms to move freelyor the hands toopen
fully indicates hypotonia.
It fades rapidly and is not normally elicited after 6
months of age.

15. ⚫Palmar/graspreflex
 Beginsat 32 weeks of gestation
 Light touch of the palm produces
reflex flexion of the fingers
 Most effectiveway -- slide the
stimulating object, such as a finger
or pencil, across the palm from the
lateral border
 Disappearsat 3-4 months
 Replaced byvoluntary graspat 45
months

16. ⚫Clinical significance
 Exceptionallystrong grasp reflex -- spastic formof cerebral
palsy & Kernicterus
 May beasymmetrical in hemiplagia & in cases of cerebral
damage
 Persistence beyond 3-4 months indicate spastic formof
palsy

17. ⚫Plantar/graspreflex
 Placing object or finger beneath the
toes causescurling of toes around the
object
 Presentat 32 weeks of gestation
 Disappearsat 9-12 months
• Clinical significance :
 This reflex is referred to as the
"readiness tester".
 Integrates at the same time that
independent gait first becomes
possible.

18. ⚫Walking/steppin
g reflex
 When sole of foot is pressed
against thecouch, baby tries to
walk
 Legs prance up & down as if baby
is walking ordancing
 Presentat birth, disappearsat
approx 2-4 months
 With daily practice of reflex,
infants may walk alone at 10
months

19. Clinical significance
Premature infants will tend to walk in a toe-heel
fashion while more mature infants will walk in a
heel-toe pattern.

20. ⚫Limbplacement reflex
 When the front of the leg below the
knee or the arm below the elbow is
brought into contact with the edge
of a table, child lifts the limbs over
theedge
 Presentat birth, fadesaway rapidly
inearly months of life
• Clinical significance
 Reflex is readilydemonstrable in the
newborn and persistent failure to
elicit it at this stage, is thought to
indicate neurological abnormality

21. ⚫Withdrawal reflex
 Protectivereflex
 Stimulus : a pinprick ora sharp
painful stimulus tosole of foot
 Response : flexion & withdrawal of
stimulated leg
 Presentat birth, persists throughout
life
 Clinical significance – Absence of
this is seen in neurologically impaired
infants.

22. ⚫Asymmetrictonic neck reflex
 Mostevident between 2-3 months of age
• Clinical significance
 The ref lex fades rapidlyand is not normally
seen after 6 months of age.
 Persistence is the most frequentlyobserved
abnormality of the infantile reflexes in
infantswith neurological lesions
 Greatlydisruptsdevelopment

23. ⚫Symmetrictonic neck
reflex
 Extension of the head causes
extensionof the fore limbs and
flexion of the hind limbs
Evident between 2-3 monthsof age
 Clinical significance
 Not normally easilyseen orelicited in
normal infants
 May be seen in an exaggerated form
in manychildren with cerebral palsy.

24. ⚫Babinski’sref lex
 Stimulus consists of a firm painful stroke
along the lateral borderof thesole from heel
to toe
 Responseconsists of movement (flexion or
extension) of the big toe and sometimes
movement(fanning) of theothertoes
 Presentat birth, disappearsatapprox 9-10
months
 Presenceof ref lex later may indicatedisease

25. ⚫Babkinreflex
 Deeppressureapplied simultaneously
to the palms of both hands while the
infant is in supine position
 Stimulus is followed by flexion or
forward bowing of the head, opening of
the mouth and closing of theeyes
 Fades rapidlyand normally cannot be
elicited after 4 months of age.

26. • Clinical significance
 Reflex can be demonstrated in the newborn, thus showing
a hand-mouth neurological link, even at thatearly stage

27. ⚫Parachute reflex
 Reflexappearsatabout 6-9 months &
persists thereafter
 Elicited by holding the child in ventral
suspension & suddenly lowering him to the
couch
 Arms extend asadefensivereaction
• Clinical significance
 Absentorabnormal in children with
cerebral palsy
 Would beasymmetrical in spastic
hemiplagia

28. ⚫Landau reflex
 Seen in horizontal suspension with the
head, legs & spineextended
 If the head is flexed, hip knees &
elbows also flex
 Appearsatapproximately 3 months,
disappearsat 12-24 months
• Clinical significance
 Absenceof reflex occurs in hypotonia,
hypertoniaor mental abnormality

29. ⚫Trunk incurvation reflex
 Stroking one side of spinal column
while baby ison hisabdomen causes
 Crawling motion with legs
 Lifting head from surface
 Present in utero, seen at
approximately 3rd or 4th day
 Persists for 2-3 months

30. ⚫Gallant’sreflex
 Firm sharp stimulation along sides of
the spine with the fingernails or a pin
producescontraction of the underlying
musclesand curving of the back.
 Response iseasilyseen when the infant
is held uprightand the trunk
movement is unrestricted
 Best seen in the neonatal period and
thereaftergradually fades.

31. ⚫Tendon ref lexes
Simple monosynaptic reflexes, which areelicited bya
sudden stretch of a muscle tendon
Occurswhen the tendon is tapped
Presentthroughout life

32. Spinal cord levels of the tendon reflexes

33. ⚫Clinical significance
 Useful diagnostically for :
Detectionof upper motor neuron lesions (exaggerated
response)
Myopathicconditions (depressed orabsent response)
Localization of the segmental lesionsof thecord.

34. ⚫Tonic labyrinthine reflex
Labyrinths -- most importantorgans
concerned with thedevelopmentof
anti-gravitypostures and balance
 Movementof the head in any
dimensionstimulates the labyrinths;
and produces the appropriate
responses
 Arms & legsextend when head moves
backwards, & will curl in when the
head moves forward
 Emerges in utero until approximately
4 months postnatally

35. Facial reflexes
⚫Nasal reflex
 Stimulationof the faceor nasal cavitywith wateror local
irritants produces apnea in neonates
 Breathing stops in expirationwith laryngeal closure in
infants – bradycardia & lowering of cardiac output
 Blood flow to skin, splanchnicareas muscles & kidney
decreases
 Flow to the heart & brain remains protected

36. ⚫Blink reflex
 A bright lightsuddenly shone into theeyes, a puff of air
upon the sensitive cornea or a sudden loud noise will
produce immediate blinking of theeyes
 Purpose – to protect theeyes from foreign bodies & bright
light
 May beassociated tensing of the neck muscles, turning of
the head away from the stimulus, frowning and crying
 Reflexes areeasilyseen in the neonate and continue to be
present throughout life

37. ⚫Clinical significance
Examination is a partof some neurological exams,
particularlywhen evaluating coma
Satisfactorydemonstrationof these ref lexes indicate –
 Nocerebral depression
 Contraction of appropriate muscles in response

38. ⚫Doll’s eye reflex
(Oculocephalic reflex)
Passive turning of the head of
the newborn leaves the eye
“behind”
 A distinct time lag occurs before
theeyes move toa new position
in keeping with the head position
 Disappearsat within aweek or
twoof birth
 Failureof this ref lex to appear
indicates acerebral lesion
Head
Eye

39. ⚫Auditoryorienting ref lex
 A sudden loud and unpleasant noise :
 Mayproduce the blink reflex
 Infant may remain still and show increased alertness
 Quietersounds usuallycause ref lexeye and head turning to the
sideof thesound, as if to locate it
 Seen firstatabout 4 months of age
 Thereafter, head turning towards sound stimuli occurs and the
accuracyof localization increases rapidly by 9-10 months

40. ⚫Clinical significance
 Reflex responses are made useof in tests of infants for
hearing loss
 Pattern of the localization responses indicates the level of
neurological maturity

41. Oral reflexes
⚫Rooting reflex
 Baby’scheek is stroked :
 They respond by turning their head
towards thestimulus
 They startsucking, thus allowing for
breast feeding
 When corner of mouth is touched, lower
lip is lowered, tongue moves towards the
pointstimulated
 When fingerslidesaway, head turns to
follow it
 Whencenterof lip is stimulated, lip
elevates

42. ⚫Onset -- 28 weeks IU
⚫Well established – 32-34 weeks IU
⚫Disappears – 3-4 months
⚫Clinical significance
Persistencecan interfere with sucking
Absenceof this is seen in neurologically impaired
infants.

43. ⚫Sucking / Swallowing
reflex
Touching lips or placing something in
baby’s mouth causes baby to draw
liquid into mouth bycreating vacuum
with lips, cheeks & tongue
 Onset – 28 weeks IU
 Well established – 32-34weeks IU
 Disappearsaround 12 months

44. ⚫Clinical significance :
Persistence may inhibitvoluntary sucking
Sigmund Freud - Any kind of deprivation of the
activitywill lead to fixation resulting in oral habits

45. ⚫Gag reflex
(Pharyngeal reflex)
 Seen in 19 weeks of IU life
 Ref lexcontraction of the back
of the throat
 Evoked by touching the roof of
the mouth, the back of the
tongue, the area around the
tonsils and the back of the
throat

46. ⚫Functional significance
 It, along with reflexive pharyngeal swallowing, prevents
something from entering the throat except as part of
normal swallowing and helps preventchoking
 Clinical significance
 Absenceof thegag ref lex -- symptom of a numberof
severe medical conditions :
 Damage to theglossopharyngeal nerve, thevagus nerve,
 Brain death.

47. ⚫Cryreflex
 Non conditioned reflex which
accounts for its lack of its
individual character
 Sporadic in nature
 Starts as earlyas 21-29 weeks of IU
life

48. ⚫Importance of cry
 It is infant’s firstverbal communication
 Can be interpreted as a messageof urgencyordistress
 Indicates:
 Hunger
 Pain
 Discomfort

49. Conclusion
Appropriate knowledgeof reflexes enablesa paedodontist
to identify whetherthechild is developing normallyor
not
to identify whetherdevelopment is going on ata proper
rateor not
 Knowledgeof abnormalities if all reflexes are notproper

51. References
⚫ShobhaTandon. Textbook of Paedodontics
⚫MS Muthu. Paediatric Dentistry, Principals & practice