This will be a prospective, descriptive study of Emergency Department patients suspected of having acute appendicitis. Initial screening of potential enrollees will be performed by ED nurses, residents, and attendings. Once consented and enrolled, a study sonographer will interview and examine the patient, preferably before lab results are available. The ultrasound must be completed and adequate images obtained before other imaging modalities are completed. Ultrasound of the right lower quadrant (RLQ) will performed using the graded compression technique described previously in the literature. All participating EP sonographers are already trained in this technique, fully credentialed and no additional training will be performed. A "Bedside" standardized data collection form will be used at the bedside to record ultrasound findings and clinical information. The sonographer will designate the appendix as "not visualized", "visualized and normal", or "visualized and abnormal" and the ultrasound as "positive for appendicitis", "negative for appendicitis" or "indeterminate" based on the exam and ultrasound findings.