What are the mechanical causes of large bowel obstruction?
The most common mechanical causes are colorectal malignancy (50%), volvulus,most commonly of the sigmoid colon (15%), adhesions (15%), and diverticular disease (10%).
Extrinsic compression from metastatic carcinoma is another cause of obstruction. External compression occurs most likely in the pelvis, secondary to gynecological malignancies.
Less frequent causes include, hernia, intussusception, benign tumor, and fecal impaction.