A positive Babinski reflex is a normal finding in infants younger than 1 year.

A positive Babinski reflex is a normal finding in infants younger than 1 year.

• A. No
• B. Sometimes
• C. Not sure
• D. Yes

Answer: (D)

The main idea is that certain reflexes change as the nervous system matures. A positive Babinski sign—where stroking the lateral sole causes the big toe to dorsiflex and the other toes to fan out—is expected in very young children. This happens because the corticospinal tract is still myelinating in infancy, so the normal downward toe curl hasn’t developed yet. As children grow and these pathways finish myelinating, the response shifts to a downward toe curl (plantar flexion). Therefore, finding a positive Babinski in an infant younger than 1 year is normal. In adults, a positive Babinski is concerning and suggests an upper motor neuron issue. So the correct answer is Yes.

The main idea is that certain reflexes change as the nervous system matures. A positive Babinski sign—where stroking the lateral sole causes the big toe to dorsiflex and the other toes to fan out—is expected in very young children. This happens because the corticospinal tract is still myelinating in infancy, so the normal downward toe curl hasn’t developed yet. As children grow and these pathways finish myelinating, the response shifts to a downward toe curl (plantar flexion). Therefore, finding a positive Babinski in an infant younger than 1 year is normal. In adults, a positive Babinski is concerning and suggests an upper motor neuron issue. So the correct answer is Yes.