How does ultrasound work?

Ultrasound image acquisition and interpretation are highly reliant on a reasonable depth of understanding of ` how ultrasound works'. Where this is lacking, there is considerable scope for confusion. In a point-of-care setting, where novice practitioners may have limited direct supervision, this may lead to significant errors in diagnosis and subsequent patient management. This paper provides a brief introduction to the underlying physical principles of ultrasound and discussion of how these principles can be used to explain typical image appearances.