A patient suffers a lesion of the right dentate nucleus. What movement disorder would be expected ipsilaterally?

• A Intention tremor and dysmetria of the right limbs ✓
• B Resting tremor of the right hand (pill-rolling)
• C Contralateral intention tremor due to double decussation
• D Truncal ataxia and gait disturbance without limb dysmetria

Explanation

The dentate nucleus is the largest and most lateral deep cerebellar nucleus, receiving input from the lateral cerebellar hemispheres (pontocerebellum). Its efferent fibers decussate in the superior cerebellar peduncle (brachium conjunctivum) to reach the contralateral red nucleus and ventrolateral thalamus, which then project back to the ipsilateral motor cortex (second decussation via the cortical motor output). Net result: dentate nucleus lesions cause ipsilateral limb dysmetria and intention tremor (two decussations cancel out). Resting tremor is a basal ganglia feature. Truncal ataxia results from vermis/flocculonodular lobe lesions.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.