Which statement best describes the startle-related Moro reflex?

Which statement best describes the startle-related Moro reflex?

• A. Arms and legs spread outward in response to a sudden stimulus, then come back in
• B. Fingers form a tight grasp around the stimulus
• C. Head turns toward the source of the stimulus
• D. Toes curl inward when the sole is touched

Answer: (A)

The startle-related Moro reflex is a primitive newborn response to a sudden stimulus. When startled, the infant momentarily extends the arms and legs outward (abduction) and then brings them back in toward the body (adduction and flexion), often crying. This two‑phase pattern exactly matches the description of arms and legs spreading outward and then coming back in, so it’s the best fit. The reflex typically appears before birth, is present at birth, and usually integrates by about six months as the nervous system matures. Other options describe different reflexes: a tight grasp of the fingers is the palmar grasp reflex, turning the head toward a stimulus relates to rooting or neck-based reflexes, and curling the toes inward when the sole is touched is the Babinski response.

The startle-related Moro reflex is a primitive newborn response to a sudden stimulus. When startled, the infant momentarily extends the arms and legs outward (abduction) and then brings them back in toward the body (adduction and flexion), often crying. This two‑phase pattern exactly matches the description of arms and legs spreading outward and then coming back in, so it’s the best fit. The reflex typically appears before birth, is present at birth, and usually integrates by about six months as the nervous system matures.

Other options describe different reflexes: a tight grasp of the fingers is the palmar grasp reflex, turning the head toward a stimulus relates to rooting or neck-based reflexes, and curling the toes inward when the sole is touched is the Babinski response.