Rooting and Sucking Reflexes.docx

8/13/2019 Rooting and Sucking Reflexes.docx

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Rooting and Sucking Reflexes

A hungry infant will turn the head to the right or left when the cheek isbrushed by a hand or facecloth. If a nipple is touched to the face -whether to the right or left, above or below the mouth-the lips andtongue will tend to follow in that direction.

These rooting and sucking reflexes should be present in all full-termbabies. As might be expected, they are more easily elicited before thanafter a feeding. The reflexes may be absent in small prematures. Absenceamong full-term infants suggests depression of the central nervous systemfrom maternal anesthesia, hypoxia, or congenital defect.

Rooting reflex

These responses usually last until the infant is 3 or 4 months old.However, the rooting response may persist during sleep until as late as 7or 8 months. At later ages, visual stimulation plays a part-babies may rootfor a bottle but may not respond to the touch of a finger.

Persistence of the response beyond the 7th month, or its reappearance

later in life, warrant thorough medical evaluation.


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While rooting and sucking reflexes are being appraised, attention shouldalso be given to the possible presence of such anomalies as a particularlysmall chin, a face that appears unusually fat in relation to a rather smallskull, peculiar dentition (such as double-fused teeth), a cleft lip or

palate, or asymmetry of the nasolabial folds. Excess salivation, mucus,and frothing always warrant attention. Feeding problems are discussedlater.

The Moro Reflex

The Moro reflex, sometimes termed a "startle" reflex, is a series ofmovements by an infant in response to a stimulus. The pattern ofmovement varies among infants, and gradually alters during the first fewmonths of life with increasing maturity. It is not possible, therefore, to

give a single description for all ages and all infants. Mitchell describedthe reflex in the infant a few days old:

The initial part of the response is extension and abduction of the upper extremities with

extension of the spine and retraction of the head. The forearms are supinated and the digits

tend to extend and fan out, with the exception of the distal phalanges of the index finger and

thumb, which may be C-shaped ... the upper extremities describe an arc-like movement,

bringing the hands towards one another in front of the body, and finally return to the position

of flexion and abduction [Mitchell, 1960, p. 9].

Sometimes there is a slight tremor or even a rhythmic shaking of thelimbs. The movement of the lower extremities is usally less pronounced.Both legs tend to extend and abduct with the upper extremities, althoughthere may be a slight movement of flexion first. If the lower extremitiesare extended when the stimulus is applied, the flexion movements maybe more readily noted.

A sudden jolting movement, such as that produced by striking themattress or table on both sides of the infant, will usually cause thestartle response. Occasionally a loud noise may precipitate the reflex.Extension of the head relative to the trunk or a sudden strong stimulusappear to be the most reliable means of eliciting the reflex.


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Moro reflex

The Moro reflex is strongest during approximately the first 8 weeks oflife. Thereafter, it becomes less pronounced. McGraw (1937) found thatmost infants change at about 90 days from the newborn phase to atransitional phase in which movements become less gross, and at about130 days to the final "body-jerk" phase. Persistence of the Moro reflexafter the 6th month should be considered suspicious and deserves carefulmedical evaluation.

The Moro response is missing or incomplete in the younger premature butshould be readily obtained in any full-term normal baby. Its absence in a

newborn may be due to a central nervous system disorder. Occasionally,an infant will display the Moro reflex on the first day, but this is followedby greatly diminished intensity of the response during the ensuing weeks,possibly because of birth injury or general muscular weakness.Occasionally cerebral edema or other factors may cause the reflex to beabsent on the first day and gradually develop during the following 4 days.In some cases of cerebral hemorrhage, the reflex may be present the firstday, disappear, and return slowly after the 6th day. These variationspoint to the value of public health nurses following up infants who have

been discharged early from the hospital after delivery.

Asymmetry of response may occasionally be noted in normal full-terminfants, but asymmetry usually suggests fracture of the clavicle orhumerus, injury to the brachial plexus, or neonatal hemiplegia. Paine(1964) points out that a defective Moro, opisthotonos, and the setting-sunsign of the eyes (only the upper half of the iris showing above the lowerlid) are the principal and probably indispensable clinical signs ofkernicterus in the first week of life. Whenever such symptoms are noted,the need for medical attention is immediate and urgent.


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Paine did not find persistence of the Moro reflex beyond the 6th month inany of the infants in his series who had homologous retardation of psychicand motordevelopment. But abnormal persistence was seen occasionallyin the presence of spastic tetraparesis, and in one infant who

subsequently developed athetosis. Touwen (1976) points out that it maybe hard to differentiate the Moro reflex from a fright response occurringlater in life. Nevertheless, the older child with a persistent Moro is at riskof having this resemblance overlooked. As an example, in teaching thechild self-feeding, the sudden extension of the arms and opening of thehands, causing the spoon to fly off in one direction and perhaps the foodin the other, may be interpreted by the caregiver or "behavior shaper" asdue to volitional, maladaptive behavior. Or it may be ascribed to thepossibility that the child is too retarded to understand what is expectedof him. In fact, this behavior may be due to elicitation of the Moro by

lack of ability to maintain the head erect so that it drops backunexpectedly, a sudden flash of sunlight on the spoon, or a loud noise orunexpected jostle of the chair or table.

In the course of routine nursing functions, no matter how gently theinfant is handled, the reflex will be elicited several times in any 24-hourperiod in a hospital nursery, during the appraisal and demonstration bathcarried out in the home by the public health nurse, or during the infant'svisits to a well-child conference.

If the infant's limbs are free to move, the hospital nurse should be alertfor the Moro response when she rolls the bassinet to display the infant atthe nursery window or when she replaces the infant in the bassinet afterchanging the crib sheet.

The public health nurse should look for the Moro reflex as she puts theinfant down just before or after demonstrating how to bathe the infant.

Extreme care should be exercised at all times in handling distressed or

premature infants, and they should receive more constant and consistentmedical surveillance. However, while feeding, when checking vital signs,and in other circumstances when the infant is subjected to slightmovements, the nurse can observe if and when the Moro appears and thecharacteristics of the response.

The Asymmetrical Tonic Neck Reflex

Articles by Gesell (1938) and Gesell and Ames (1960) contain descriptionsof the asymmetrical tonic neck reflex. These authors assert that it is

present in practically all infants during the first 12 weeks of life, oftenspontaneously manifested by the quiescent baby in the supine position as


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A persistent asymmetrical tonic neck reflex is potentially a veryhandicapping disability. The child is prevented from seeing both handssimultaneously unless measures are instituted to position the head andhands in midline. The effort to bring food or any object to the mouth is

also inhibited. The influence of the pattern on the legs obviously posessevere restriction on the ability to achieve standing and walking.

Since the newborn needs gentle cleansing of the face, neck, and areaaround the ears several times in a 24-hour period, the nurse has manyopportunities to watch for the asymmetrical tonic neck response as sherotates the head of the infant in supine to cleanse first one side of theface and then the other. An observant nurse can discern whether theasymmetrical tonic neck reflex is present, whether the response isstronger on one side than the other, and whether it is compulsory or

persistent.

If the body response seems dependent on the head position in serialobservations of an infant over 6 months of age, the nurse should ascertainwhether the reflex has persisted. Waving a bright toy first to the rightand then to the left of the child is an effective way to elicit activerotation of the head. With young infants it is a bit easier to use a passivehead rotation maneuver.

Observation for the asymmetrical tonic neck reflex pattern provides

opportunity for carefully examining the child's neck to note the possiblepresence of torticollis or webbing. A particularly short neck in relation tothe rest of the body is also worth noting.

Finally, it is of interest to note that the early and normal tendency of theinfant to extend the "face arm" places the hand in an excellent positionto be viewed without effort. Even during the first few days and weeks oflife, many normal infants may be observed maintaining attentive eyecontact for minutes at a time with the hand they are facing while in this

position. "Learning" that the hand is there, at the end of the arm, is afirst step toward later learning what can be done with a hand.

The Neck-Righting Reflex

As the asymmetrical tonic neck response is "lost," it is replaced with aneck-righting reflex, in which passive or active rotation of the head toone side is followed by rotation of the shoulders, trunk, and pelvis in thesame direction. In the true neck-righting response, there is a momentarydelay between the head rotation and the following of the shoulders, as

opposed to the automatic, sudden, and complete body rotation in


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immediate response to a passive turn of the head that may occur in someabnormal states.

Neck-righting reflex

The nurse may observe the two-step righting response in the normal childof 1 or 2 years, as he voluntarily gets up to a sitting position from thesupine. First, he turns the head, then the shoulders, trunk, and pelvis,before undertaking the more complicated series of maneuvers by whichhe rolls over and achieves sitting (and/or rises from the floor in thequadrupedal manner). Paine et al. (1964) found that the neck-rightingreflex was obtainable in all normal infants by 10 months of age and wasgradually covered up by voluntary activity, making the age of itsdisappearance difficult to gauge. However, they point out that a neck-righting reflex in which the response is much stronger with the head toone side than to the other is not seen in normal infants; nor should theresponse at any age be so completely invariable that the baby can berolled over and over. Stereotyped reflexes of this type are consideredpathologic and are often found in infants with cerebral palsy.

It also is relevant to note that infants with low muscle tone (hypotonicity)

or with considerable excess of tone (hypertonicity) and infants with anobligatory asymmetrical tonic neck reflex would be impeded fromdemonstrating a normal neck-righting reflex.

Posture in Ventral Suspension and the Landau Reflex

All normal neonates display some evidence of tone when suspended in theprone position. The nurse may observe this when the baby is turned toprone during the nursery admission cleansing procedure. Public healthnurses may assess tone as they weigh and measure the baby at well-child

clinics or while bathing the child at home. As the newborn infant isturned to prone, with the trunk or abdomen supported, the legs should be


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flexed. While the head may sag below the horizontal and the spine beslightly convex, the infant should not be completely limp and collapseinto an inverted U.

As the baby becomes a little older, the head and spine are maintained ina more nearly horizontal plane. There is a gradual increase in thetendency to elevate the head as if to look up, while the spine remainsstraight. Still later, there is elevation of the head well above thehorizontal and arching of the spine in a concave position. Paine et al.(1964) found that the head was above the horizontal in 55 percent oftheir series at 4 months and in 95 percent at 6 months. The spine was atleast slightly concave in approximately half of the 8-month-olds, butconcavity was noted universally at 10 months. Many physicians designatethis posture, with the back slightly arched, as a "positive Landau"

(Touwen, 1976). Dissolution of the reflex is difficult to ascertain since itis gradually covered up by struggling or other voluntary activity.

The Landau reflex is tested in a different way by others. While holdingthe infant in ventral suspension with the head, spine, and legs extended,the nurse then passively flexes the head forward. The reflex is consideredpresent if the whole body then flexes. The reflex may be seen as early as3 to 4 months but should be present after 7 months of age. In general,the nurse will find that holding the infant in ventral suspension providesmore useful information than elicitation of the Landau by means ofpassive flexion of the head. In any event, the nurse's report to thephysicians should describe exactly what was done and the infant'sresponse. Whatever the infant's age, his limp collapse into an inverted Uwhen held in ventral suspension should be called to immediate medicalattention.

The Parachute Reflex and Optical Placing of the Hands

There is a tendency to refer to the parachute reflex when the behaviors

being elicited and the reactions being described are actually thoseassociated with the optical placing reaction of the hands. Touwen (1976)calls attention to and describes the difference between the two.

In each instance, the infant is held in vertical suspension and suddenlylowered toward a flat surface. The normal positive response is a forwardextension of both arms and dorsiflexion of the infant's hands during themovement. The difference between the two is that, in the optical placingreaction, the infant is permitted to see where he is going. This responsemay be noted as early as 3 months of age. In the true test for the

parachute response, the maneuver is the same but the child's visualattention is first attracted to a bright toy displayed in front of and a little


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above him and he is then suddenly plunged downward. Under thesecircumstances the parachute response may not be seen until about 6 oreven 9 months of age. Touwen (1976) suggests that the earlierappearance of the positive response, when the child can anticipate

visually that he is going down to a flat surface, illustrates the reinforcingeffect of visual on vestibular input. Since the older infant tends to smileor chuckle under anticipatory circumstances but may be frightened whenunexpectedly plunged, the former is usually the method of choice by thenurse in eliciting the presence of the reflex. If the child is plungedsideward as well as downward to the flat surface, the influence of theoptical factors is reduced. Under these circumstances, partial responsemay be noted as early as 3 months. The complete response begins a littlelater; it will be noted in most infants by 9 months and in all normalinfants by 12 months (Paine et al., 1964). In any event, the nurse should

describe in her report exactly the way in which the parachute waselicited. An asymmetrical or absent response warrants medical appraisal.

Parachute reflex


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Public health nurses are alerted to watch fathers at play with theirchildren, as the game of "so high" or "airplane" may provide theopportunities to observe for the presence and character of the parachutereflex, as well as for extensor tone in ventral suspension. Nurses who

have developed a warm rapport with the child and family may themselvesplay with the infant in this fashion, since most infants respond with greatglee.

Palmar grasp AND Planter grasp

"Palmar and Plantar Grasp

Palmar and plantar grasp are strong automatic reflexes in full-termnewborns. They are elicited by the observer placing a finger firmly in thechild's palm or at the base of the child's toes. The palmar grasp responseweakens as the hand becomes less continuously fisted, merging,sometime after 2 months, into the voluntary ability to release an object

held in the hand. The plantar response disappears at about 8 or 9 months,though it may persist during sleep for a while thereafter. Possibleabnormality may be suspected in asymmetry of response. While there is atendency to fisting in the neonate, this should not be evident at all times.Serial observation of infants in the nursery should reveal relaxation ofboth hands at some point, usually during or right after feeding, orperhaps when asleep. These appraisals provide additional opportunitiesfor detecting abnormalities of color such as cyanosis of the extremities,edema, simian palm crease (a straight line rather than an M-shape acrossthe palm), and possible malformations of the hands and feet. Persistent

edema of the feet is always worth noting, particularly if occurring in a


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female child, as it may signal the presence of a chromosomal abnormality(X. 0. Turner's syndrome).

Simian palm crease

Traction Response

Physicians test the traction response by placing the infant in supine, thendrawing him up by the hands to a sitting position. Normally, assistance bythe shoulder muscles can be felt and seen. The newborn's head lagsbehind and drops forward suddenly when the upright posture is reached.Even in the newborn period, however, there should be sufficient headcontrol to bring it back upright, and greater control is expected with age.The nurse in testing the neonate may gently raise the infant from supinein this way, in order to note the presence, absence, or asymmetry ofresponse; but she should avoid reaching the midline point, which causesthe head to drop forward suddenly.

Supporting Reaction

The supporting reaction is elicited by holding the infant vertically andallowing his feet to make firm contact with a table top or other firmsurface. The "standing" posture includes some flexion of the hip and knee.Automatic stepping may also be observed when the newborn is inclinedforward while being supported in this position. During the first 4 monthsof life, the crouching position gradually diminishes; this is followed byincrease in support, so that normal infants will usually support asubstantial propor- tion of their weight by 10 months (Paine, 1964).


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Supporting reaction and stepping

In this supported standing position, it is to be expected that a few infantswill stand on their toes from time to time or occasionally cross or "scissor"their legs. However, consistent standing on the tips of the toes orscissoring of the legs after 4 months of age may be considered an index ofsuspicion warranting medical attention. A club foot or a deformity at theknee or hip may also become apparent while the supporting reaction is

being appraised.

By the age of 6 months, the supporting reaction is less easilydemonstrable, and by 10 or 11 months, it is difficult to distinguish fromvoluntary standing.

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Rooting and Sucking Reflexes.docx