Ultrasound (US) is the preferred imaging modality in the pediatric ED in the diagnostic evaluation of girls with suspected pelvic pathology. In the transabdominal approach, urine acts as a sonographic acoustic window to image the adnexa and uterus, but this requires a full bladder. Many high acuity pelvic pathologies presenting to the pediatric ED have significant morbidity and mortality associated with delays in diagnosis. Despite this, diagnostic pelvic US is often delayed by the need to fill the bladder, awaiting a patient's report of subjective sensation of bladder fullness. Images of the bladder using POCUS can be easily obtained at the bedside by emergency physicians, providing a quick assessment of the size and shape of the bladder that may be a more accurate, objective measure of bladder fullness. We aim to assess the utility of POCUS of the bladder compared to patient's sensation of bladder fullness in this clinical scenario.