Medical Diagnostic Signs

Babinski Sign

The Babinski Reflex is  a normal response in infants up to the age of 2, in which the big toe extends upwards and backwards, while the other toes fan outwardly; however, in adults a positive Babinski Sign is pathological and often indicative of severe damage to the central nervous system.

In order to test for a Babinski Sign or Babinski Response: firmly rub the lateral aspect of the sole of the foot with a firm (but blunt) instrument, such as the back of a pen. The pen should be rubbed from one end of the sole of the foot over the curve and through to the toes. This will elicit the following three potential responses:

Extension of the big toe, in which the big toe extends upwards, while the other toes curl outwards. In infants up to the age of 2 this is a normal primitive response and is associated with the under-developed or immature central nervous system. With an Adult however, this is a pathological response, indicating severe damage to the Central Nervous System.

No Response: Indicates damage to the peripheral nervous system, muscles, or tendons within the region.

Flexion: the toes all curve inwards. This is the normal response produced in healthy adults with a fully developed and functional central nervous system.

Comparison of the Babinski Sign in Adults and Infants

In adults the Babinski Sign can indicate upper motor neuron diseases, such as lesions, which affect the corticospinal tract. The cause of this damage can be varied, however, a Positive Babinski Sign will often be the only indication of upper motor neuron disease, and will cause a Neurologist to consider other neurological investigations, such as Lumbar Punctures, MRIs and CT scans to determine cause and treatment.  In infants, an extension response, or Positive Babinski response  is common because the corticospinal pathway is not fully myelinated, which means that messages are not conducted through the neurological pathway as rapidly, and consequently, the primitive reflex is not inhibited by the cerebral cortex. The extensor response changes to a flexion response during the first 1-2 years of life, depending on natural development of the central nervous system.

Cushing’s Triad

Identifies significant indication of raised ICP, often a late sign. Includes: Respiratory changes/ Irregularities, Widened Pulse Pressure, and Bradycardia.

Kehr’s Sign

Kehr’s sign is the presense of shoulder tip pain associated with abdominal pain and often relates to refered pain from organ injury or damage within the abdomen.