Chess Knight Move

A woman with a minor injury was at the hospital because her doctor said she wanted to take a closer look at it to make sure everything was all right. The woman's husband sits patiently in the waiting room.
After a few minutes, the doctor comes out and asks her assistant for a wrench, which understandably concerns the husband.
Then, after a couple more moments, the doctor re-enters the room, this time asking for a screwdriver. The husband grows worried and begins to pace in circles. Then, a little later, the doctor bursts through the doors screaming for a hammer and at that, the husband, in a state of frenzied fear, runs up and asks, 'Doctor, what the heck is wrong with my wife?'
'I don't know,' replies the flustered doctor, 'I can't get my bag open!'