Yes , I agree you need to perform full assessment and examination ,however you should have the skill / competency to differenate between upper motor neurn lesion and lower motor neuron lesion when you have doubts as youu seem have with this patient .

As well , ask your patient if the symptoms ( numbness) in both lower limbs are the same degree or one more than the other .

In few cases it is difficult to differnate . Also ,in some cases of severe Central Nervous System sensitivity numbness , pain and tingling could be tied together in upper and lower quarters .

cheers
Emad