Extensor plantar responses, also known as the Babinski sign or phenomenon, is a neurological reflex that occurs when the sole of the foot is stimulated. It is characterized by the dorsiflexion or upward movement of the big toe, accompanied by the fanning out or spreading of the other toes.
This reflex is normally present in infants until the age of 1 to 2 years, when their nervous system is still maturing. However, in adults and older children, the presence of extensor plantar responses is considered abnormal and may indicate damage or dysfunction in the upper motor neurons.
The extensor plantar response is commonly assessed by using a blunt object, such as the edge of a reflex hammer, to stroke the sole of the foot from the heel towards the toes. In a normal response, the toes flex or curl downwards, and the foot arches inwards. This is referred to as a flexor or normal plantar response.
However, in the presence of upper motor neuron lesions or certain neurological conditions, the Babinski sign emerges. Instead of flexing, the big toe dorsiflexes or extends upwards, while the other toes splay outwards. This is indicative of an abnormal extensor or Babinski sign.
The presence of extensor plantar responses can be indicative of underlying conditions such as spinal cord injury, brain injury, multiple sclerosis, brain tumors, stroke, or neurodegenerative disorders. It is an important clinical sign that helps healthcare professionals assess and diagnose neurological disorders.
