A middle-aged man walks into your clinic complaining of weakness. You take a moment to observe his gait. What do you notice?

This should generate a hypothesis. 

You reference your framework for weakness and try to determine the location of the lesion to narrow your differential diagnosis. The patient’s gait has already provided a clue (spasticity). 

So you check his reflexes next. 

The hyperreflexia suggests an upper motor neuron lesion. Next, you check for Hoffmann’s sign, which if present, would suggest a cervical lesion.

You have just diagnosed cervical myelopathy. Using only your eyes and a reflex hammer.