How does ultrasound imaging create a cross-section view instead of a top view?

[Shaybay92]

Homework Statement

I'm having trouble understanding exactly how the image goes from a transducer to the screen... When they put the transducer on the top of your stomach say, does this give a cross section view, from the side of your body rather than a top view as you would expect? Because if it gave a top view, how would the distances etc form a picture? It would all be in the one spot

 

[berkeman]

Homework Statement

I'm having trouble understanding exactly how the image goes from a transducer to the screen... When they put the transducer on the top of your stomach say, does this give a cross section view, from the side of your body rather than a top view as you would expect? Because if it gave a top view, how would the distances etc form a picture? It would all be in the one spot

So the transducer must not be 1-dimensional. What do your google and wiki searches turn up for ultrasound transducers? If you were going to design one to show those displays, how would you do it?