What is an Ultrasound?

As a photographer, I have always been fascinated with how ultrasounds can create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs. Did you know that the first ultrasound was developed to measure flaws in metal castings in the 1940s? I am also mesmerized by the fact that 3D ultrasounds can make live, moving images of a beating heart. You probably know that ultrasound does not penetrate bone well. And for that reason, because of the cranium, it has very limited use on the brain. Creating an ultrasound requires three processes: producing the sound wave, receiving echoes from it, and then interpreting those echoes.