Moro reflex


The Moro reflex is an infantile reflex normally present in all infants/newborns up to 3 or 4 months of age as a response to a sudden loss of support, when the infant feels as if it is falling.

It involves three distinct components:

The reflex is initiated by pulling the infant up from the floor and then releasing him, he spreads his arms, he pulls his arms in and he cries at 10 seconds.

It involves three distinct components:

spreading out the arms (abduction)

unspreading the arms (adduction)

crying (usually)

It is useful in evaluating integration of the central nervous system.

The Moro reflex is distinct from the startle reflex.

It is believed to be the only unlearned fear in human newborns.

It may be observed in incomplete form in premature birth after the 28th week of gestation.

It is usually present in complete form by week 34.

The absence or asymmetry of either abduction or adduction is abnormal, indicates a profound disorder of the motor system or a generalized disturbance of the central nervous system.

The persistence of the reflex in older infants, children and adults is abnormal.

An absent or inadequate Moro response on one side is found in infants with hemiplegia, brachial plexus palsy, or a fractured clavicle, and its persistence of the beyond 4 or 5 months of age is noted only in infants with severe neurological defects.

Persistence and exacerbation of this reflex is common in cerebral palsy.

The reflex is impaired in the early stage of kernicterus and it is absent in the late stage of kernicterus.

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