Hemorrhoids are swollen or inflamed veins of the anus or lower rectum. An internal hemorrhoid occurs within the anus, while an external hemorrhoid occurs in the skin surrounding the anus. Symptoms of hemorrhoids include bleeding, pain during bowel movements, and/or itching1. It is estimated that “about 75% of people will have hemorrhoids at some point in their lives”2.
Figure 5.71 Hemorrhoids3
The first 55 seconds of the following video does a nice job of illustrating what hemorrhoids are and how they develop.
Video: Hemorrhoids - http://www.youtube.com/watch?v=C8vZoIhQCwU
The anus and lower rectum experience high pressure during bowel movements. Thus, hemorrhoids are believed to be caused by straining during bowel movements. To prevent this condition from occurring, it is recommended that people consume a high-fiber diet, drink plenty of water, and exercise to produce regular, large, soft stools. In addition, people should "go" at first urge and not wait until it is more than an urge2.