What is Lhermittes Sign?

Lhermitte's sign is characterized by a specific sensation described as a "shocking" or "electric" feeling that occurs during neck flexion. This phenomenon is typically associated with irritation of the spinal cord, often seen in conditions such as multiple sclerosis or cervical spondylotic myelopathy. The mechanism involves a conduction disturbance in the spinal cord, particularly affecting the pathways that transmit sensory signals.

When a person flexes their neck forward, this motion can stretch the spinal cord and the surrounding tissues, triggering the abnormal sensation. It does not manifest as dizziness, loss of taste, or isolated tingling in the hands; rather, it is a distinctive experience primarily tied to neck movement. Thus, identifying Lhermitte’s sign accurately as the shocking sensation during neck flexion is critical for diagnosing underlying neurological conditions.