If the hemroids originates at the top (rectal side) of the Excretory Orifice canal, it is referred to as an internal hemroids. If it originates at the lower end of the Excretory Orifice canal near the Excretory Orifice, it is referred to as an external hemroids. Technically, the differentiation between internal and external hemroids is made on the basis of whether the hemroids originates above or below the dentate line (internal and external, respectively).
As discussed previously, hemroidsal cushions in the upper Excretory Orifice canal are made up of blood vessels and their supporting tissues. There usually are three major hemroidsal cushions oriented right posterior, right anterior, and left lateral. During the formation of enlarged internal hemroids, the vessels of the Excretory Orifice cushions swell and the supporting tissues increase in size. The bulging mass of tissue and blood vessels protrudes into the Excretory Orifice canal where it can cause problems. Unlike with internal hemroids, it is not clear how external hemroids form.
What are the causes of Piles ?
It can be hereditary with congenital weakness of the vein walls.
In men, due to erect posture there is high pressure in rectal veins.
Straining by constipation and over purgation.
Dysentery may aggravate latent hemroids.
Haemorrhoids are also common among pregnant women. The pressure of the foetus in the abdomen, as well as hormonal changes, cause the haemorrhoidal vessels to enlarge.