How damage to the lower portion of the spinal cord affect defecation?

Explanation

Damage to the lower portion of the spinal cord produces a loss of voluntary control over defecation due to disruption of the somatic nerves to the skeletal muscle of the external anal sphincter. When fecal matter distends the rectum, it initiates the defecation reflex, but the damage to the somatic nerves leaves the external sphincter in an uncontracted state. Under these conditions, defecation occurs whenever the rectum becomes distended.