The anal canal is the last 4 centimeters thru which stool passes as it goes from the rectum to the outside world. The anus is the opening of the anal canal to the outside world. Hemorrhoids that cause issues are found similarly in males and females, and their superiority tops between forty five and 65 years old. The arteries supplying blood to the anal canal descend into the canal from the rectum above and form a rich network of arteries that communicate with one another round the anal canal. Due to this rich network of arteries, hemorrhoidal blood vessels have a prepared supply of arterial blood. This explains why bleeding from hemorrhoids is bright red ( arterial blood ) instead of dark red ( venous blood ), and why bleeding from hemorrhoids often can be serious.

The dentate line is a line in the anal canal that implies the change from anal skin ( anoderm ) to the liner of the rectum.

If the hemorrhoid originates at the top ( rectal side ) of the anal canal, it is known as an internal hemorrhoid. If it originates at the lower end of the anal canal close to the anus, it is named an external hemorrhoid. Technically, the differentiation between external and internal hemorrhoids is formed on the premise of whether the hemorrhoid originates above or below the dentate line ( external and internal, respectively ).


In the formation of enlarged internal hemorrhoids, the vessels of the anal cushions swell and the supporting tissues increase in size.


The prominent mass of tissue and blood vessels sticks out into the anal canal where it may cause issues