A patient suffers a hemisection of the spinal cord at T6 on the right side (Brown-Séquard syndrome). Which deficit is expected in the left lower limb?

• A Ipsilateral spastic paralysis below the lesion
• B Contralateral loss of pain and temperature sensation ✓
• C Ipsilateral loss of pain and temperature sensation
• D Bilateral loss of vibration sense

Explanation

In Brown-Séquard syndrome (hemisection), the spinothalamic tract (which carries pain and temperature) decussates within 1-2 segments of entry in the spinal cord, so loss of pain and temperature occurs contralateral to the lesion. The dorsal columns (vibration, proprioception) and corticospinal tract (voluntary motor) do not cross until the medulla, so their deficits are ipsilateral. Therefore, a right T6 lesion causes contralateral (left) pain/temperature loss below T6.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.