The fanning out and curling in of the sole of baby's feet upon stroking, is called.............

Question

Accepted Answer

The correct option is 4: Babinski reflex

The Babinski reflex is the precise, correct term for the involuntary movement described in the question, which is an essential part of the newborn neurological examination. This primitive reflex, named after the French neurologist Joseph Babinski, is reliably triggered by applying a firm, upward stroke to the sole of the baby's foot, along the outer border. The characteristic positive response, which signals a normally developing nervous system in an infant, is the big toe moving upward (a movement called dorsiflexion) while the other toes fan out or spread apart. This reaction is normal and expected until the baby is approximately 1 to 2 years old. Its presence is a temporary sign of the immaturity of the central nervous system's corticospinal tract. As the child's brain matures and the inhibitory motor pathways fully myelinate, the Babinski reflex disappears and is replaced by the adult plantar reflex, where the toes will instead curl downward. Therefore, this toe-fanning response upon sole-stroking is the defining feature of the Babinski reflex.

The incorrect option is 1: Moro reflex

The Moro reflex, often referred to as the "startle reflex" or "embracing reflex," is a protective, whole-body response, not a foot-specific reflex. It is usually elicited by a sudden change in position, like the sensation of falling, or an abrupt loud noise. The characteristic response involves the baby rapidly extending their arms outwards with open palms (abduction) and then immediately bringing them back toward the body (adduction), in a motion that looks like an embrace, often followed by a cry. This reflex is present from birth but typically disappears by five to six months of age. As you can see, this major reflex involves the arms and trunk and has no connection to the fanning and curling action specifically on the sole of the foot.

The incorrect option is 2: Grasp reflex

The Grasp reflex is a response primarily associated with the hands, though a similar reflex exists in the feet. The Palmar Grasp reflex is elicited when an object or finger applies sustained pressure to the baby's palm, causing the fingers to curl inward and grasp the object tightly. While there is a related Plantar Grasp reflex when pressure is applied to the ball of the foot, the toes curl *downward* in a gripping motion. Crucially, the Grasp reflex never involves the combination of the big toe moving *upward* and the other toes *fanning out*. The Grasp reflex in the hand disappears around five to six months, and the one in the foot disappears around nine to twelve months, but neither matches the unique description of the movement caused by the Babinski reflex.

The incorrect option is 3: Rooting reflex

The Rooting reflex is one of the crucial reflexes for newborn survival and is entirely focused on the feeding mechanism. This reflex is stimulated by gently stroking or touching the baby's cheek or the corner of the mouth. The involuntary response is for the baby to turn their head and open their mouth in the direction of the touch, in an attempt to "root" out and locate a source of food, such as the mother's nipple. This reflex helps the baby successfully latch and begin feeding. It is typically lost around four months of age as feeding becomes a voluntary behavior. As it is a reflex involving the head and mouth, it is completely unrelated to any action performed on the sole of the foot.