This will be a prospective, observational study of adult ED patients suspected of having a SBO. ED nurses, residents, and attendings will perform the initial screening for potential enrollees. Once consented and enrolled, a study sonographer will interview and examine the patient, preferably before labs and AXR results. The ultrasound must be completed and adequate images obtained before advanced imaging modalities are completed. Ultrasound of all four abdominal quadrants will be performed using the "mowing the lawn" technique described previously in the literature (4).