Final answer:
The lesion is likely located in the spinal cord at the level of the lumbar enlargement, specifically affecting the motor neurons that control the legs. The symptoms of contralateral leg weakness, urinary incontinence, and abulia suggest an upper motor neuron (UMN) lesion.
Step-by-step explanation:
Based on the symptoms described, the lesion is likely located in the spinal cord at the level of the lumbar enlargement. The presence of contralateral leg weakness with sparing of the face and arms suggests an upper motor neuron (UMN) lesion. The additional symptoms of urinary incontinence and abulia further support this diagnosis. The specific location of the lesion would be in the ventral horn of the lumbar enlargement, affecting the motor neurons that control the legs.