Sonography, another name for ultrasound scanning, is a diagnostic imaging method that creates images of the interior of the body using high-frequency sound waves. In the medical field, it is commonly used to check and diagnose disorders that influence blood flow, organs, and tissues. Although ultrasound has uses in many other medical fields, it is very frequently used in obstetrics to track fetal development throughout pregnancy.

Sound Waves: Using a transducer or probe, ultrasound equipment produces high-frequency sound waves that are inaudible to humans.
Echoes: These sound waves pass through bodily tissues and reverberate off of solid bodily structures, fluids, or organs.
Image Formation: The transducer receives the returning echoes and transmits the information to a computer. After that, the computer decodes the echoes to produce real-time visuals, which are frequently shown on a monitor.

2D Ultrasound: Provides flat, black-and-white images that give a good overview of organs or a fetus.
3D Ultrasound: Captures three-dimensional images, adding more depth and detail.
4D Ultrasound: Shows a real-time moving 3D image, particularly popular in obstetrics for viewing fetal movement.
Doppler Ultrasound: Measures the direction and speed of blood flow, helpful in assessing blood vessels and heart conditions.