Mesoth.net - There are two types of hemorrhoids external and internal which are differentiated via their position with respect to the dentate line.
External hemorrhoids are those that occur outside the anal verge (the distal end of the anal canal). Specifically they are varicosities of the veins draining the territory of the inferior rectal arteries, which are branches of the internal pudendal artery. They are sometimes painful, and often accompanied by swelling and irritation. Itching, although often thought to be a symptom of external hemorrhoids, is more commonly due to skin irritation. External hemorrhoids are prone to thrombosis: if the vein ruptures and/or a blood clot develops, the hemorrhoid becomes a thrombosed hemorrhoid.
Internal hemorrhoids are those that occur inside the rectum. Specifically they are varicosities of veins draining the territory of branches of the superior rectal arteries. As this area lacks pain receptors, internal hemorrhoids are usually not painful and most people are not aware that they have them. Internal hemorrhoids, however, may bleed when irritated. Untreated internal hemorrhoids can lead to two severe forms of hemorrhoids: prolapsed and strangulated hemorrhoids. Prolapsed hemorrhoids are internal hemorrhoids that are so distended that they are pushed outside the anus. If the anal sphincter muscle goes into spasm and traps a prolapsed hemorrhoid outside the anal opening, the supply of blood is cut off, and the hemorrhoid becomes a strangulated hemorrhoid.
Internal hemorrhoids can be further graded by the degree of prolapse.
- Grade I: No prolapse.
- Grade II: Prolapse upon defecation but spontaneously reduce.
- Grade III: Prolapse upon defecation, but must be manually reduced.
- Grade IV: Prolapsed and cannot be manually reduced.
Lorenzo-Rivero S (August 2009). “Hemorrhoids: diagnosis and current management”. Am Surg 75 (8): 635–42. 19725283.
E. Gojlan, Pathology, 2nd ed. Mosby Elsevier, Rapid Review series.
Banov L, Knoepp LF, Erdman LH, Alia RT (1985). “Management of hemorrhoidal disease”. J S C Med Assoc 81 (7): 398–401. 3861909.
By : dr. Norman Hoffman
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