Ruling out free air under the diaphragm (e.g. perforated ulcer)
Ruling out radio-opaque<unk>  foreign body (e.g. swallowed battery)
Ruling in bowel obstruction (i.e. to avoid need for subsequent CT scan)
Acute abdominal series
FAST exam
Diagnostic peritoneal lavage
Ultrasound: Abdomen
EFAST exam
Gastric lavage
Theraputic peritoneal lavage
Anoscopy