Definition

The definition of constipation includes the following: infrequent bowel movements (typically <3 times per week), difficulty during defecation (straining during more than 25% of bowel movements or a subjective sensation of hard stools), or the sensation of incomplete bowel evacuation.

Causes of constipation

• Blockages in the colon or rectum
• Anal fissure 
• Bowel obstruction: colon cancer or rectal cancer
• Narrowing of the colon (bowel stricture); may be related to diverticulum or inflammatory bowel disease (IBD)
• Difficulty with the muscle involved in elimination
• Dietary issues -- inadequate water or fiber
• Systemic disease
• Diabetes
• Hyperparathyroidism and hypothyroidism  
• Problems with the nerves around the colon and rectum
• Multiple sclerosis  
• Parkinson's disease
• Spinal cord injury
• Stroke