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Medical Term:

startle reflex


a primitive reflex response observed in the normal newborn but typically suppressed by 3–4 months of age. Any sudden stimulus (a loud noise, a blow to the supporting surface, or being dropped 5–10 cm through space) causes flexion of the hip and knee joints with fanning of the fingers followed by fist clenching and extension of the upper limbs followed by flexion.

Synonym(s): Moro reflex, parachute reflex, startle reaction

See Also: cochleopalpebral reflex

© Copyright 2017 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.