Which pattern of impairment is most characteristic of Brown-Séquard syndrome caused by a left hemisection at T10?

Which pattern of impairment is most characteristic of Brown-Séquard syndrome caused by a left hemisection at T10?

• A. Bilateral loss of motor function with preserved proprioception and light touch
• B. Bilateral loss of pain and temperature with preserved motor function
• C. Ipsilateral loss of motor function and proprioception with contralateral loss of pain and temperature sensation below the lesion
• D. Ipsilateral loss of pain and temperature with contralateral loss of motor function and proprioception

Answer: (C)

Brown-Séquard syndrome from a unilateral spinal cord hemisection produces a distinctive pattern because of how the tracts run on each side. The corticospinal tract and the dorsal columns on the injured (left) side are responsible for motor control and proprioception/vibration; when they are disrupted, you get ipsilateral weakness or paralysis and loss of position/vibration on the same side below the lesion. The spinothalamic tract, which carries pain and temperature, crosses to the opposite side shortly after entering the cord. Those fibers from the right side have already crossed, so a left-sided lesion causes contralateral loss of pain and temperature starting a couple of segments below the lesion. So, on a left T10 hemisection, you’d expect left-sided motor impairment and loss of proprioception below T10, plus right-sided loss of pain and temperature below about a few levels lower. This combination uniquely reflects Brown-Séquard syndrome.

Brown-Séquard syndrome from a unilateral spinal cord hemisection produces a distinctive pattern because of how the tracts run on each side. The corticospinal tract and the dorsal columns on the injured (left) side are responsible for motor control and proprioception/vibration; when they are disrupted, you get ipsilateral weakness or paralysis and loss of position/vibration on the same side below the lesion. The spinothalamic tract, which carries pain and temperature, crosses to the opposite side shortly after entering the cord. Those fibers from the right side have already crossed, so a left-sided lesion causes contralateral loss of pain and temperature starting a couple of segments below the lesion.

So, on a left T10 hemisection, you’d expect left-sided motor impairment and loss of proprioception below T10, plus right-sided loss of pain and temperature below about a few levels lower. This combination uniquely reflects Brown-Séquard syndrome.