Small bowel obstruction (SBO)

Adhesion (most common cause)

Hernias (2nd most common cause, but most common in patients with a virgin abdomen)

Extrinsic causes:

Intra-abdominal abscess

Hematoma

Annular pancreas

Endometriosis

Malrotation with Ladd's band

Midgut volvulus

Carcinomatosis or tumor encasement from nonsmall bowel source

Superior mesenteric artery syndrome

Intussusception

Intrinsic causes:

Small bowel tumors

Congenital: small bowel atresia, stenosis, mesenteric cyst, Meckel diverticulum

Inflammatory obstruction: meconium ileus, gallstone ileus, foreign body (bezoars)

Large bowel obstruction

Extrinsic: volvulus, adhesions, hernia, endometriosis

Intrinsic: colon cancer, ulcerative colitis, diverticulitis, radiation enteritis

Intraluminal: meconium ileus, intussusception, fecal impaction, foreign body, barium