Final answer:
The three most common causes of small bowel obstruction are adhesions, hernias, and neoplasms. Adhesions are often a result of surgery, hernias arise from weaknesses in bodily tissues, and neoplasms include benign or malignant tumors.
Step-by-step explanation:
The three most common causes of small bowel obstruction are adhesions, hernias, and neoplasms. Adhesions can form after abdominal surgery, creating bands of scar tissue that may constrict parts of the small intestine. Hernias, which occur when an internal part of the body pushes through a weakness in the muscle or surrounding tissue wall, can also lead to an obstruction if the small intestine becomes trapped. Neoplasms, or tumors, both benign and malignant, can obstruct the small bowel by physically blocking the passage of intestinal contents. Other less common causes include Crohn's disease, causing inflammation and strictures, volvulus (twisting of the intestine), and intussusception (when one part of the intestine slides into another).