An ultrasound scan is a medical test that uses high-frequency sound waves to create live images from the inside the body. Also called a sonogram or sonography, ultrasounds let doctors see the body’s soft tissues, which X-rays can’t do.

Doctors order ultrasounds for many reasons, such as to look for the causes of pain, swelling, and infection. Ultrasound scans are safe and painless.

An abdominal ultrasound uses sound waves to make images of the abdomen (belly).

An ultrasound machine sends sound waves into the abdominal area and images are recorded on a computer. The black-and-white images show internal structures such as the appendix, intestines, liver, gall bladder, pancreas, spleen, kidneys, and bladder.

Doctors order an abdominal ultrasound when they’re concerned about symptoms such as belly pain, repeated vomiting, abnormal liver or kidney function tests, or a swollen belly. The tests can show them the size of the abdominal organs and help them check for injuries to or diseases of the organs.