Which tract carries fine touch and proprioception, often affected in Brown-Sequard syndrome?

Which tract carries fine touch and proprioception, often affected in Brown-Sequard syndrome?

• A. Dorsal column medial lemniscus.
• B. Lateral corticospinal tract.
• C. Spinothalamic tract.
• D. Vestibulospinal tract.

Answer: (A)

Fine touch and proprioception travel in the dorsal column–medial lemniscus pathway. After entering the spinal cord, these sensory fibers ascend ipsilaterally through the dorsal columns (fasciculus gracilis for the lower body, fasciculus cuneatus for the upper body) to the medulla, where they synapse in the gracile and cuneate nuclei. They then cross to form the medial lemniscus and continue to the thalamus before reaching the somatosensory cortex. In Brown-Sequard syndrome, this tract on the side of the lesion is damaged, leading to loss of fine touch and proprioception on the same side below the level of injury. The other tracts have different roles: motor control via the lateral corticospinal tract, pain and temperature via the spinothalamic tract (which typically affects the opposite side), and balance/posture via the vestibulospinal tract.

Fine touch and proprioception travel in the dorsal column–medial lemniscus pathway. After entering the spinal cord, these sensory fibers ascend ipsilaterally through the dorsal columns (fasciculus gracilis for the lower body, fasciculus cuneatus for the upper body) to the medulla, where they synapse in the gracile and cuneate nuclei. They then cross to form the medial lemniscus and continue to the thalamus before reaching the somatosensory cortex. In Brown-Sequard syndrome, this tract on the side of the lesion is damaged, leading to loss of fine touch and proprioception on the same side below the level of injury. The other tracts have different roles: motor control via the lateral corticospinal tract, pain and temperature via the spinothalamic tract (which typically affects the opposite side), and balance/posture via the vestibulospinal tract.