A women of 35-years, comes to emergency depament with symptoms of pain in abdomen and bilious vomiting but no distension of bowel. Abdominal X-ray showed no air fluid levels. Diagnosis is

Abdominal pain, bilious vomiting without abdominal distention is suggestive of proximal small intestinal obstruction, distal to ampulla of Vater (Duodenal obstruction) Nausea and vomiting are more common with proximal obstruction Abdominal distention is more common in distal obstruction