Physical Therapy Assistant Practice Exam

What reflex might hinder a normal eight-month-old infant's ability to ambulate?

1. Palmar grasp reflex

2. Stepping reflex

3. Plantar grasp reflex

4. Babinski reflex

The correct answer is: Plantar grasp reflex

The plantar grasp reflex is significant in the development of an infant's motor abilities, particularly regarding ambulation. This reflex involves the flexing of the toes in response to pressure on the soles of the feet. While it may seem like a normal part of reflexive behavior, if this reflex persists beyond the typical age of integration, it can hinder an infant’s ability to walk. At around eight months, infants are expected to develop muscle strength, coordination, and postural control necessary for standing and stepping. If the plantar grasp reflex is still active, it can interfere with the necessary extension of the toes and the activation of the muscles that are crucial for walking. The presence of this reflex can also lead to improper foot positioning, which is detrimental to the development of a normal gait pattern. In contrast, the palmar grasp reflex primarily affects the hands and does not directly influence lower extremity mobility. The stepping reflex, though related to walking behavior, typically aids in the preparation for ambulation rather than hindering it. The Babinski reflex, also primarily a reflex of the toes, generally indicates neurological development and will integrate as the child matures. Thus, the plantar grasp reflex is the primary reflex that can limit an eight-month-old's ability to amb