Background: Ultrasonography (US) is highly dependent on operators’ skills. It is not only a matter of correct scan techniques; there are anatomical structures and variants, as well as artifacts, which can produce images difficult to interpret and which, if not properly understood, can be causes of errors. Objectives: This paper will review relatively common US pitfalls and artifacts that can be encountered in trauma patients and will offer tips to recognize and avoid them. Discussion: Normal anatomical structures and anatomical variants can mimic fluid collections or perisplenic lesions. Examination along multiple scan planes, real-time observation of movements or repetition of the study after the patient has drunk some fluid or after placing a finger on her/his body wall can help proper identification. The term artifact in US imaging refers to display phenomena not properly representing the imaged structures. This can result in images suggesting fracture lines within organs or at their borders, lung consolidations, or pleural effusions, and abdominal fluid collections. Their knowledge is the first step to recognize them; then, use of multiple scan planes or repetition of the study after voiding or changes of equipment setting can make them disappear or clarify their nature. Conclusion: We present possible anatomic pitfalls and artifacts that may affect correct interpretation of US images in patients with abdominal trauma and suggest how to avoid or to clarify them during the examination. Knowing their existence, their appearances, and the reasons why they are produced is important for proper use of this diagnostic technique.
