Case 9: Question 2

A 39-year-old woman went to see her family physician complaining of weakness in her legs. She said her legs felt tired when she stood up too long. She first noticed the weakness three months earlier. Examination revealed increased reflexes in both legs and bilateral Babinski signs. There was marked weakness of foot,ankle and calf muscles, but thigh muscles did not show definitive weakness. Sensory examination revealed mild deficits in all modalities in both lower legs.

Question 2: Where could a single CNS lesion be located to cause this clinical presentation?