انت هنا الان : شبكة جامعة بابل > موقع الكلية > نظام التعليم الالكتروني > مشاهدة المحاضرة

Classifications of reflexes

الكلية كلية التمريض     القسم قسم التخصصات التمريضية     المرحلة 3
أستاذ المادة عبد المهدي عبد الرضا حسن الشحماني       11/07/2018 07:51:00
classifications of reflexes

a) primitive reflexes and genetic sub-programs

1. reflex responses to light touch:
light touch produces a variety of reflex responses, depending upon the area stimulated and the age of the individual. the motor responses are most marked in the early months of life.

• grasp reflex (palmar and plantar):
light touch of the palm or sole produces reflex flexion of the fingers or toes. the most effective way to elicit the reflex is to slide the stimulating object, such as a finger or pencil, across the palm or sole from the lateral border. a beautiful neurological organization of the palmar grasp reflex has been described, in which finger flexion follows a definite sequence: “middle - ring – little – index – thumb”.
chain responses follow the initial reflex producing two further stages, which are seen best in the palmer reflex. the first follows initial flexion of the digits and consists of tensing of the flexed muscles to produce a strong grasp. a strong tonic component at this stage of the reflex ensures maintenance of the grasp as long as the stimulus persists. the second stage occurs when traction is exerted by the stimulating finger or pencil. this is followed by a progressive contraction of the arm muscles, which is sometimes so strong that the baby can be lifted from the examination couch. the palmer and planter grasp reflexes are easily demonstrable in the neonate but then fade rapidly and become seldom seen after 4 or 5 months of age. phylogenetically, the reflex is suggested to have a survival value by enabling the infant animal to cling to the mother s fur.
• placing reflex:
stimulation of the dorsum of the foot of the neonate produces complete flexion of the same leg. probably, the easiest way to show this and the method used in clinical examination, is to hold the infant upright and to let the dorsum of the foot touches the lower side of the edge of the examination table. the infant flexes the leg and appears to do so in order to place the foot on the table. this reflex is readily demonstrable in the newborn and persistent failure to elicit it at this stage, is thought to indicate neurological abnormality. it should fade rapidly in the early months of life.

• rooting reflex:
light touch of the cheek or stimulation of the edge of the mouth, results in turning of the head in the direction of the stimulus and simultaneous opening of the mouth and extension of the tongue. it is sometimes called the “cardinal-points reflex” because it is elicited by stimulation of all four quadrants around the mouth. the reflex appears to have an adaptive and survival function.
utilization of the reflex during feeding ensures that the infant takes the nipple well into his widely opened mouth and so avoids painful pressure upon the nipple end. unjustified haste over breast feeding or other faulty techniques which prevent use of this reflex lead to incomplete acceptance of the nipple into the infant s mouth and cause discomfort. the reflex is demonstrable in the newborn period and then fades during the early months. it has been found valuable to use this reflex to obtain an indication of the infant s alertness by noting its ease of elicitation.


2. reflex response to pressure and pain:
although some of the responses to pressure serve a constructive and functional role (such as the support reaction), the majority has a protective and survival value (such as the withdrawal response). many of these responses are so well ingrained that only the most profound cerebral depression inhibits them. for example, the persistent absence of balance response in the neonatal period indicates severe disturbance and a poor prognosis during infancy and childhood.

• gallant s reflex:
firm sharp stimulation along sides of the spine with the fingernails or a pin produces contraction of the underlying muscles and curving of the back. this response is easily seen when the infant is held upright and the trunk movement is unrestricted while the stimulus is applied. it is best seen in the neonatal period and thereafter gradually fades.

• withdrawal reflex:
a pinprick or other sharp painful stimulus to the sole of foot of an extended leg, results in uncontrolled flexion and withdrawal of the stimulated limb. this response should not be confused to tickling. positive reaction is normal up to 2 months of age. the protective value of the reflex is obvious.

• crossed extension reflex:
if the leg is kept extended at the knee, while the sole of the foot is stimulated by firm strokes with a finger or other firm object, the opposite leg flexes and then extends. because the extension phase is associated with some adduction at the hip, an impression is obtained of the moving leg crossing the stimulated once, as if to push away the stimulating hand. this reflex is present in the neonate and even in the premature baby. the reflex gradually fades during the first 6 months but it is difficult to ascribe a precise time, after which it is no longer seen.

• babinski (planter) reflex:
this reflex is one of the fundamental signs of classical neurology. the stimulus consists of a firm painful stroke along the lateral border of the sole from heel to toe. the response consists of movement (flexion or extension) of the big toe and sometimes movement (fanning) of the other toes. techniques have been described to elicit the response by stimulating other areas (e.g. stroking the lateral border of the dorsum of the foot, squeezing the calf or running the fingers along the anterior border of the tibia). these maneuvers are most effective when the reflex is pathologically exaggerated.
the reflex is present throughout life. in the first year or two, the surface area from which stimuli are effective is quite extensive. thereafter, it shrinks until the lateral side of the sole is the principle area from which a response can be obtained. the motor response is similarly widespread at first so that movement of all the toes is noticeable and extension of the big toe usually predominates over the weaker flexion movement. after this age, however, the motor response becomes more controlled and restricted.

• magnet (traction) reflex:
steady firm pressure is applied to the sole of the foot or to the palm of the hand with the limb flexed and is then gently withdrawn, will be followed by extension of the limbs, as if being drawn forwards by a magnet.

• babkin reflex:
the stimulus for this reflex consists of deep pressure applied simultaneously to the palms of both hands while the infant is in an appropriate position, ideally supine. the stimulus is followed by flexion or forward bowing of the head, opening of the mouth and closing of the eyes. the reflex can be demonstrated in the newborn, thus showing a hand-mouth neurological link, even at that early stage. it fades rapidly and normally cannot be elicited after 4 months of age.

• stepping reflex:
pressure upon the sole of the foot of the neonate causes first flexion then extension of the leg. as this occurs on alternate side, an impression is created of automatic of the stepping. it is not true walking however, because there is no trunk support or pelvic stability this is acquired through the support reflex that develops later. head position has been proven to affect the ease of elicitation, strength and duration of the reflex. the stepping reflex should disappear by 6 months of age. this reflex sometimes persists for many years in children with cerebral palsy, merely demonstrating the persistence of a primitive reflex.

• support reflex (legs):
the similarity of this reflex to the magnet reflex was mentioned earlier. when an infant is held vertically and the soles of the feet are allowed to come into contact with a table or floor, the pressure on the soles causes reflex extension of the legs. a chain response, producing secondary stiffening of the legs, follows the initial reaction and makes the legs as strong supporting pillars. this complex reflex is important for the development of the upright posture and locomotion.
the reflex is elicited with difficulty in the early months of age and even when it is obtained it lasts only within a few brief moments. it gradually becomes more evident as the stepping reflex fades and by 6 months of age, it should be obtained easily and persists for several minutes. failure of this reflex to appear at the right time delays locomotor development. on the other hand, persistence long after it has served its purpose is a sign of neurological abnormality and produces characteristic abnormal gait patterns.

• support reflex (arms):
support reflex appears in the arms several months later after the similar reflex in the legs. as the body is tilted forwards or sideways, extension of the arms occurs. contact of the palms of the open hands with firm surface provides the stimulus for tensing of the arm muscles. visual and labyrinthine righting reflexes are responsible for the early part of the reflex and support follows pressure stimulus on the palms.


3. reflex responses to kinesthetic stimuli:
many reflex responses originate from stimuli from the tendons, muscles and joints. most of these reflexes are important for the maintenance of posture and orientation of the body in space.

• tendon reflexes:
these are simple monosynaptic reflexes, which are elicited by a sudden stretch of a muscle tendon such as occurred when the tendon is tapped. they are present throughout life and are most useful diagnostically for the detection of upper motor neuron lesions (exaggerated response), myopathic conditions (depressed or absent response) and localization of the segmental lesions of the cord.

table (1): spinal cord levels of the tendon reflexes.
reflex cord level
biceps (elbow) c5,6
brachioradialis c5,6
triceps c6,7
long finger flexors c8-t1
hip abductors l2,3,4
quadriceps (knee) l2,3,4
gastrocnemius-soleus (ankle) s1,2

• eye righting (doll’s eye) reflex:
passive turning of the head of the newborn leaves the eye “behind” and a distinct time lag occurs before the eyes move to a new position in keeping with the head position. within a week or two of birth, this doll’s eye phenomenon has disappeared as a result of an eye-righting reflex. failure of this reflex to appear indicates a cerebral lesion. although this reflex is listed with the reflex responses to kinesthetic stimuli, it is probable that the labyrinthine also has a major influence on the reflex.
• moro reflex:
this is one of the best known and most useful of all the neonatal reflexes. the afferent stimulus is a sudden movement of the head on the shoulders, which can be produced in several ways. one way is to allow the head to droping about 25 mm into the palm of the hand. another way is to raise the supine baby a short way from the couch by pulling upon the hands and then releasing them suddenly. the response consists of wide abduction of the arms and opening of the hands. within moments, the arms come together again. the response often includes tensing of the back muscles, flexion of the legs and crying.
the response should be symmetrical. asymmetry indicates a central or peripheral nervous system lesion or injury to the bones or muscles of the defective arm. failure of the arms to move freely or the hands to open fully indicates hypotonia. weakness of response occurs with hypotonia and pre-maturity. the reflex is present at birth and its persistent absence or asymmetry in a newborn should cause considerable concern. it fades rapidly and is not normally elicited after 6 months of age.

• asymmetric tonic neck reflex (atnr):
the stimulus which initiates this reflex consists of sideway turning of the head, either passively or actively. the response consists of extension of the arms on the side to which the head turns and flexion of the opposite arm. similar movements occur in the legs. the precise age at which this reflex appears continues to be the subject of controversy. it is most evident between 2 and 3 months of age.
this reflex would seem to play an important role in visumotor development. it is present during the time that visual fixation upon nearby objects is developing and it seems that the nervous system is making sure that the appropriate arm stretches out towards visualized objects. as the hand touches the object, the seeds are shown of awareness of distance (at arm’s length) and eye-hand co-ordination. the reflex fades rapidly and is not normally seen after 6 months of age. persistence of the atnr is the most frequently observed abnormality of the infantile reflexes in infants with neurological lesions. its persistence, usually in an exaggeratedly strong form, is a clear indication of abnormality of the nervous system and greatly disrupts development.

• symmetrical tonic neck reflex (stnr):
experimental observations of animals have shown that flexion and extension of the head can profoundly influence the posture of the animal. the response has been linked with their feeding needs and habits. when the reflex is strong in an experimental dog for example, flexion of the head causes flexion of the fore limbs and extension of the hind limbs, just as if the animal was bending the head forward in order to take food. on the other hand, extension of the head produce extension of the fore limbs and flexion of the hind limbs, just as if the animal was preparing to take a tasty morsel held above him. this reflex is not normally easily seen or elicited in normal infants but may be seen in an exaggerated form in many children with cerebral palsy.

• head-body and body-head righting reflexes:
as mentioned earlier, various stimuli may produce the same response. orientation of the head in relation to the body and vice versa is so important that it is not surprising to be produced by several righting reflexes. some of them arise from kinesthetic stimulation of the muscles and joints of the neck. as the head is turned, the trunk realigns itself, so as to remain in normal relationship to the head.
similarly, turning of the trunk is followed by reorientation of head position. these righting reflexes are present early in life and during the second half of the first year of life, as they reinforce the action of the visual and labyrinthine righting reflexes. a clear understanding of the righting reflexes is necessary for the treatment of young children with central neurological disorders. for example, in the case of a child who cannot roll sideways, it is necessary to study these reflexes to know whether it is therapeutically better to rotate the head and have the trunk follow or vice versa.


4. reflex responses to visual and auditory stimuli:
as our visual and auditory senses are able to receive stimuli from a distance, they are well equipped to act as warning mechanisms. consequently, many of the reflexes produced by visual and auditory stimuli have a protective and survival value.

• blink reflex:
a bright light suddenly shone into the eyes, a puff of air upon the sensitive cornea or a sudden loud noise will produce immediate blinking of the eyes. there may be associated tensing of the neck muscles, turning of the head away from the stimulus, frowning and crying. these reflexes are easily seen in the neonate and continue to be present throughout life.

• visual righting reflex
once some visual awareness of orientation has developed, infants do not readily tolerate distorted views and reflexly attempt to right their head position in order to correct the view. this visual righting reflex develops in close association with the labyrinthine righting reflexes.

• auditory orientating reflexes:
a sudden loud and unpleasant noise may produce the blink reflex or the infant may remain still and show increased alertness. quieter sounds usually cause reflex eye and head turning to the side of the sound, as if to locate it. this auditory orientation reflex is seen first at about 4 months of age. thereafter, head turning towards sound stimuli occurs and the accuracy of localization increases rapidly by 9-10 months the sound source is located directly within about 5° of accuracy. these reflex responses are made use of in tests of infants for hearing loss. the pattern of the localization responses indicates the level of neurological maturity.
5. reflex response to labyrinthine stimuli:
the attainment and maintenance of upright postures against gravity are essential requirements for the successful motor development of the human infant. the labyrinths are the most important organs concerned with the development of anti-gravity postures and balance. movement of the head in any dimension stimulates the labyrinths and after the early weeks of life, it produces the appropriate responses.

• labyrinthine head righting:
once this reflex developed, the infant’s head is always moved into a position, in which the vertex is uppermost and the mouth horizontal, whatever the position of the child. thus, if the infant is held by the feet with the trunk and head downward, the head will be extended backwards in order to get it upright against gravity. similarly, if the infant is held in ventral suspension, i.e. horizontally with a hand supporting the trunk, the head will be extended to achieve an upright posture. the response elicited in this latter position has been described as the “landau reflex”.
labyrinthine head righting is not present at birth but develops during the early months of life. its influence is clearly seen in the progressive ease with which the infant raises his head in the prone position. in humans, head righting responses also occur in response to visual stimuli, so that when observing the motor development of infants, it is difficult to know the relative contributions made by these two head righting mechanisms. those children who fail to develop any head righting ability at all, such as some children with cerebral palsy, are very disabled in consequence. the development of head righting and the ability to control the head position irrespective of gravity opens up great possibilities for further motor development.
a series of chain reactions ensue as various reflexes influence the body position and the attitudes and movements of the limbs. for example, once an infant can raise his head in the prone position, the way is open for him to crawl. the sequence is as follows: (head righting - increases in strength and extent until shoulders are raised - this facilitates forward movement of arms - support reflex of arms then enables chest to be raised - this facilitates raising of pelvis - leads to drawing up of knees - then support reflex enables pelvis to be raised - as security of support increases, limbs can be freed in succession to develop an alternating reciprocal movement - crawling is achieved).

• tonic labyrinthine reflexes:
the labyrinths are thought to exert a tonic influence upon the distribution of muscle tone throughout the body and to control the balance between the extensor and flexor muscles. it is very difficult to isolate and study these effects in normal infants but the effects of their disturbance are very obvious in neurologically damaged infants, many of whom exhibit dystonic syndromes.


b) postural reactions

growing evidence suggests that these behaviors might be better considered as genetic subprograms, existing at various levels of integration. whether these behaviors are reflexes or subprograms, postural reactions remain as life-long influences on the posture-movement dynamic.

1. ventral suspension behaviors:
a) “landau reflex”: it causes an infant held in ventral suspension to move from head, spine and leg extension to flexion of the hips, knees and elbows, when the head is depressed. this reflex appears at 3 months and integrated at 6 months.
b) “parachute reaction”: it occurs when the child is held in ventral suspension and quickly lowered. the child responds by extending the arms to protect against falling. it appears at 6 months and persists throughout life.
the landau and the parachute behaviors are foundations of protective, support and righting reactions.

2. equilibrium reactions:
the equalization of opposing forces to maintain balance is attained by visual, vestibular and other kinesthetic inputs:
a) visual equilibrium reactions:
visual equilibrium reactions of the upper extremities appear at 3 months, while those of the lower extremities appear at 4 months. these visual equilibrium reactions aid in placing, orientation and motion compensation. the visual equilibrium reactions persist throughout life.

b) vestibular reactions:
* protective equilibrium reactions: maturation of these reactions brings the individual to the human bipedal stage of motor development. they occur when muscle tone is normalized and provide body adaptation in response to change of center of gravity in the body. protective equilibrium reactions respond to multiple sensory inputs and especially to vestibular stimuli. they appear between 4 and 18 months and persist throughout life:
- “downward protective extension” appears at 4 months.
- “forward protective extension” appears at 6 months.
- “sideward protective extension” appears at 9 months.
- “protective staggering and shifting” appears at 15 to 18 months.
* tilting equilibrium reactions: they appear between 6 and 21 months and persist throughout life:
- “prone tilting reaction” appears at 6 months.
- “supine tilting reaction” appears at 8 months.
- “quadruped tilting reaction” appears at 10 months.
- “standing tilting reaction” appears after 12 months.

c) postural stabilization reactions:
they occur in response to visual and vestibular stimuli but kinesthetic feedback is essential. postural stabilization reactions begin proximally and progress distally. postural stabilization equilibrium reactions are similar to titling equilibrium reactions in their times of appearance.


المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .