Neurologic Localization Checklist

• Cranial nerve involvement present (e.g., facial sensory loss or weakness, diplopia, dysphagia/dysarthria, hearing loss, vertigo)?

  • Localize: intracranial (brain/brainstem).
  • Imaging: head/brain first; do not image T/L spine.

• Arm weakness or numbness present?

  • Localize: brain, brainstem, cervical cord, brachial plexus, or peripheral nerve (not T/L cord).
  • Clues: face involvement → brain; dermatomal pain/paresthesia → cervical radiculopathy; diffuse hyperreflexia/spasticity → cervical myelopathy.
  • Imaging: brain and/or cervical spine per exam; avoid T/L spine.

• Leg weakness or numbness present?

  • Localize: brain, brainstem, spinal cord, root, plexus, or peripheral nerve (broad differential).
  • Use additional findings (reflexes, sensory level, sphincters, back/neck pain) to direct imaging.

• Reflexes increased, pathologic, or pyramidal signs (Babinski, Hoffmann, clonus, spasticity)?

  • Localize: upper motor neuron lesion (brain or spinal cord), not peripheral nerve.
  • Imaging: MRI brain and/or spine per distribution.

• Altered mental status (confusion), language disturbance (aphasia), neglect, personality or memory change?

  • Localize: systemic/metabolic or brain; not spinal/peripheral.
  • Workup: check systemic causes (glucose, electrolytes, infection, toxins); image brain if focal signs or unexplained.

• “Crossed” findings (ipsilateral cranial nerve deficit with contralateral body weakness/sensory loss)?

  • Localize: brainstem.

• Laterality matches lesion site?

  • Cerebral hemisphere: deficits contralateral to lesion.
  • Spinal cord: motor usually ipsilateral to lesion with tract-specific sensory patterns; for quick triage, assume same side for motor.

• Bilateral weakness (legs, or arms and legs) with preserved sensation?

  • Localize: anterior spinal cord (anterior spinal artery syndrome) until proven otherwise.
  • Look for: sphincter dysfunction, pain/temperature loss, preserved vibration/position.

• Sensory level on exam (a distinct band where sensation changes)?

  • Localize: spinal cord at or just below that dermatome.

• Distal symmetric sensory loss/weakness with reduced/absent reflexes and no UMN signs?

  • Localize: peripheral neuropathy/neuromuscular junction/muscle rather than CNS.
  • Consider: EMG/NCS if unclear.

• Mixed findings that span both sides without a clear level?

  • Reassess for multifocal disease (metabolic/toxic), but if some signs are left and others right, think brainstem.

Imaging/Triage Quick Rules

• Cranial nerve findings ± facial involvement → image head/brain; skip spine.
• Arm-only deficits without cord features → consider brain/cervical studies; avoid T/L spine.
• Red flags for cord compression (back/neck pain, sensory level, UMN signs, sphincter dysfunction) → emergent MRI spine at suspected level.
• Acute focal deficit in stroke window → stroke protocol: non-contrast head CT ± CTA; escalate per findings.
• Subacute focal cortical signs (aphasia, neglect, seizures) → MRI brain with/without contrast.

Practical Notes

• Base localization on patterns; do not fixate on tract names.
• Document side, distribution (face/arm/leg), reflexes, sensory level, and sphincters to narrow site efficiently.