Riddle: Why should doctors attend to window-sashes?
This riddle was created to completely confuse you. You may not be able to make a similarity between the doctor and the window-sashes, that’s okay. Doctors should attend to window-sashes because they have so many panes(pains). First of all, a window sash is the part of a window that moves and holds the glass panes together.
The sash fits inside the window frame, which is attached to the house. On the other hand, pain is a highly unpleasant physical sensation caused by illness or injury. It refers only pain to doctors and just to confuse the readers given panes.
The answer is: Because they have so many panes (pains).