Bowel obstruction in elderly lady

An 84-year-old female presented with a 2-day history of abdominal pain, vomiting, and constipation/obstipation. She had a prior history of abdomino-perineal resection for carcinoma of rectum 15 years ago. On examination, the abdomen was distended with increased bowel sounds. There was increased tenderness in the medial aspect of the thigh, no palpable inguinal mass, or any evidence of hernia. Clinical diagnosis of bowel obstruction, likely secondary to recurrence of carcinoma rectum or from adhesions due to prior surgery was considered. Further evaluation with plain radiograph and CT scan was requested to determine the cause of small bowel obstruction.