Lhermitte Sign – Dorsal Column Pathology — SCE Neurology MCQ

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EasyMultiple Sclerosis & CNS InflammationLhermitte Sign – Dorsal Column PathologySCE Neurology

A 60-year-old man with known MS presents with the Lhermitte sign (electric shock-like sensation down the spine on neck flexion). MRI cervical spine shows a demyelinating lesion at C2–C3. What anatomical structure is responsible for this symptom?

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Correct answer: D — Dorsal columns (posterior columns) of the cervical spinal cord

Lhermitte sign is caused by demyelination (or other pathology) affecting the dorsal (posterior) columns of the cervical spinal cord. Neck flexion stretches the demyelinated axons, generating ectopic impulses that are perceived as electric shock-like sensations radiating down the spine and limbs. While classically associated with MS, it can also occur with cervical spondylotic myelopathy, radiation myelopathy, B12 deficiency, and other cervical cord pathologies. A: The spinothalamic tract mediates pain/temperature, not the electric shock sensation. C: Corticospinal tract carries motor signals. D: Spinocerebellar tracts carry proprioceptive information to the cerebellum. E: Anterior horn cells are lower motor neurones.

Reference: NICE NG100 MS (2022); Clinical Neuroanatomy