reflexes, primitive

The "primitive reflexes" are those that appear and disappear in an expected order during infant development. They are important signs of a normally functioning nervous system when present at the right stage of development; likewise, abnormal absence of an expected reflex at a given stage of infant development, or presence of (or reappearance of) a reflex beyond the normal time it is normally found implies some abnormal function of the nervous system.

Moro reflex, startle reflex	the infant is placed in a semiupright position and the head is momentarily allowed to fall slightly backward into the examiner's hand; the child will symmetrically fling the arms out from the body and flex the thumbs, followed by a reverse flexion of the arms as if grasping onto his mother. An asymmetric response may signify a fractured clavicle or a birth injury to the nerves of the arm which does not function properly. Absence of the Moro reflex in a newborn is an ominous finding, implying some sort of serious neurologic condition. See also main heading here.
grasp response	is obtained by placing a finger or object in the open palm of each hand; a normal infant will grasp the object and will resist attempted removal with a tighter grip. This reflex is sometimes strong enough in a really vigorous baby to briefly support the child's body weight as if he were doing pull-ups (do not try this at home).
tonic neck reflex, fencing reflex	is produced by turning the baby's head to one side while he lies on his back; he extends his arm on the side to which the head is turned, and flexes the other arm, in a pose that mimics a fencer. For an infant to remain in a constant tonic neck response is always abnormal.
parachute reflex	the child is suspended by the trunk and suddenly lowered as if the child were falling for an instant. The child spontaneously throws out the arms as a protective mechanism. The parachute reflex appears before the onset of walking.
rooting reflex	the newborn's cheek is lightly stroked, and he turns to find the expected mother's nipple
sucking reflex	a finger or artificial nipple is placed in the newborn's mouth, and he does what comes naturally
Babinski reflex or sign	a finger is stroked firmly down the outer edge of the baby's sole; the toes spread and extend out.

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