Which description matches the tonic neck reflex?

• A. Extension of the limbs on the side toward which the head is turned with flexion on the opposite side
• B. The infant raises both arms above the head when startled
• C. The infant sweeps the arm toward the face when the cheek is touched
• D. All four limbs extend and rotate in the same direction

Answer: (A)

Tonic neck reflex, specifically the asymmetric tonic neck reflex, is tested by turning the infant’s head to one side. When the head turns toward one side, the limbs on that face side extend while the limbs on the opposite side flex, creating a fencing posture. This pattern reflects how the nervous system links head position with limb posture in early development and is typically present at birth, fading by about 4 to 6 months as maturation occurs.

So the described pattern—extension of the limbs on the side the head is turned toward with flexion on the opposite side—fits ATNR perfectly.

For context, the other options describe different reflexes: the startled arming motion is characteristic of the Moro reflex; turning toward a cheek stimulus is the rooting reflex; and extending all four limbs in the same direction points to a different primitive/reflex pattern, not the asymmetric neck reflex.