A lesion at the dorsal column nuclei (nucleus gracilis and cuneatus) in the lower medulla would impair which sensory modality contralaterally?

• A Pain and temperature
• B Crude touch only
• C Visceral sensation
• D Proprioception and fine discriminative touch ✓

Explanation

Second-order neurons for proprioception, vibration, and discriminative touch originate in the nucleus gracilis (lower limb) and nucleus cuneatus (upper limb) in the medulla. Their axons cross as the internal arcuate fibers to form the medial lemniscus before ascending to the thalamus. A lesion here would thus impair these modalities on the contralateral side below the level of decussation.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.