Real-time ultrasound—that is, imaging of the child in motion—has been available as a clinical tool since 1976. The room for the ultrasound examination consists of a conventional examining table, as well as the ultrasound imaging device itself:—the bulky-appearing machine here. Now the pregnant woman is positioned on the table for the examination. The abdomen is suitably draped.
The head of the instrument is now placed over the uterus; this device in turn consists, basically, of a crystal—which sends out pulsing, high-frequency sound waves—and a transducer which collects the echoes of these waves. The echoes are then collated by a computer, which in turn assembles them into a recognizable image of the living unborn child. And the child can be imaged by either a linear scan, which is useful for later pregnancies, or a sector scan, which is more accurate for delineating the child in an early pregnancy, such as this one.