A 23-year-old man is stabbed in the neck. Once stabilized, his MRI shows a right hemisection of the cord at C6. What is the expected result of this injury?
A. Paralysed diaphragm
B. Absent sensation to temperature in the left hand
C. Paralysis of the left hand
D. Absent sensation to light touch in the left hand
E. Brisk right biceps reflex
Ans: Lesion localization
(B )Hemisection of the cord is also known as Brown–Séquard syndome. This results in ipsilateral paralysis and loss of light touch and vibration sensation and contralateral loss in pain and temperature below the point of the lesion. The spinothalamic tracts cross at the level of the cord, so sensation to pain and temperature is lost in the contralateral limbs (B). C3, 4, 5 keep the diaphragm alive (A), so breathing should be preserved. As the right corticospinal tract has been severed, the right, ipsilateral hand would be paralysed (C) as well as the right leg. The left dorsal columns carry light touch fibres from the left limb (D). They have been unaffected by the injury. C6 is responsible for the biceps reflex and would be lost (E). Reflexes distal to the lesion would be brisk.