What are hemorrhoids

Hemorrhoids, or piles, are small swellings or tumors, occurring at the anal margin, in the anal canal, or in the lower part of the rectum, and are primarily a varicose condition of the hemorrhoidal
plexus, or hemorrhoidal veins.

This may be followed by other pathologic changes which are characteristic of the different varieties; nevertheless, all varieties possess certain pathologic olmnges in common.

They all arise from certain pathologic changes in the veins in a manner similar to that occurring in varicose veins in other parts of the body.

In some specimens the walls are thickened, in others extremely thinned. The former condition is due exceptionally to a hyperplasia of the unstriped muscular fibers; much more frequently the contractile tissue has either diminished, or has completely disappeared, and is replaced by a lax connective structure.

Certain veins thus show their coats transformed into a mucous tissue, others have their structure traversed by a fibrillar meshwork. Two changes are constantly found-a considerable, thickening of the wall, and formation of granulations which
grow into the lumen and deform it. Less frequently, the thickened walls are made up solely of fibrous tissue. Such alterations are to be found in the veins as well as the venules.

Thinning on the other hand, while visible in veins of all calibers, is especially manifest in those of large size, forming the reddish circles which muay be seen with the naked eye on cross-section
of a hemorrhoidal mass. The vein wall is reduced to a thin layer of fibrous tissue, sometimes totally separate from the tissues in the vicinity, at others indistinguishable.

Contiguous veins of equal size have their walls fused together at their point of contact; as a result, where several veins or venules
meet, their walls have become incorporated with the fibrous tissue in the vicinity, and seem to have disappeared. A11 that can be seen are irregular recesses excavated in fibrous groundwork, and
separated from each other by partitions also fibrous in nature. Thus a true cavernous tissue is produced by sclerosis of the veins, fusion of their walls, and the budding of the connective tissue into the enlarged and deformed vascular cavities. Most those sclerosed veins undergo dilatation, though some are totally obliterated, other merely diminised in caliber.

The pathologic, changes occurring peculiar to the different varieties according to location are divided into external and internal hemorrhoids.

The external variety may be divided into two classes: the thrombotic and the connective tissue or hypertrophied skin tabs. These two types are located at the anal margin and lower part of the anal canal, and are covered by stratified squamous ephithelial cells.

The thrombotic pile usually coms on suddenly and is a bluish-red color, very painful, covered by skin and contains a clot of blood.

The connective tissue or skin tab type is pathologically what the name implies.

Internal hemorrhoids are located in the upper hart of the anal canal and the lower part of the rectum, and are surrounded by mucous membrane which is lined by columnar epithelium. The walls
of the dilated veins between the numerous venous spaces are very thin. After the hemorrhoids have existed for a long while, other patllologic changes
occur, thus the mucous membrane becomes thickened and its histological character is much changed.

There is a tendency to fibrosis, and when the protruding mass is constricted by the sphincter ani msucle, the pile becomes much swollen, and there is a marked edema with thrombosis resulting from partial strangulation. When the blood supply is completely cut off from the protruding pile, gangrene or sloughing follows.