Hemorrhoids are dilated veins within the anal canal and distal area of rectum. Internal hemorrhoids are derived from the internal hemorrhoidal plexus above the dentate line and are covered by rectal mucosa. External hemorrhoids are derived from the external hemorrhoidal plexus below the dentate line and are covered by stratified squamous epithelium.

An exact cause is unknown; however, the upright posture of humans alone forces a great deal of pressure on the rectal veins, which somtimes causes them to bulge. Other contributing factors include: Aging, Chronic Constipation or Diarrhea, Pregnancy, Heredity, Faulty bowel function due to overuse of laxatives or enemas; straining during bowel movements. Spending long periods of time (e.g. reading) on the toilet. Whatever the cause, the tissues supporting the veins stretch. As a result, the veins dilate; their walls become thin and bleed. If the stretching and pressure continue, the weakend veins protrude.

First degree - No prolapse.
Second degree - Condition prolapses but reduces spontaneously.
Third degree - Reduces with manual reduction.
Fourth degree - Permanently prolapsed, will not reduce.

Bright red bleeding with defecation, external protrusion, tenderness (severe pain when thrombosed), itching, burning, and soilage.