In 4 patients, trauma to the lumbosacral area produced abnormalities similar to those seen after resection of the nervi erigentes. Mechanisms of the resulting constipation and fecal incontinence for liquid stools included a prolonged transit time through the entire colon, a low rectal pressure, spasticity of the anal canal, and abnormal anal reflexes. Previous trauma to the lower spine must be considered in the differential diagnosis of chronic constipation.