Lesion of the right lateral medulla (Wallenberg syndrome) produces loss of pain and temperature over the right face and left body. The tract responsible for contralateral body sensory loss travels in the:

• A Right anterior spinothalamic tract
• B Left lateral spinothalamic tract
• C Right posterior column (fasciculus cuneatus)
• D Right lateral spinothalamic tract ✓

Explanation

In Wallenberg syndrome the right lateral spinothalamic tract is interrupted at the medullary level; this tract has already crossed in the spinal cord, so it carries pain/temperature from the left body. The ipsilateral face involvement arises from the right spinal nucleus/tract of CN V. The posterior columns carry proprioception and are not damaged in a lateral medullary infarct.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.