From Biology-Online Dictionary | Biology-Online Dictionary


noun, plural: haemorrhoids

(1) A type of portacaval anastomoses which forms between the superior rectal vein (of portal circulation) and the middle rectal veins and inferior rectal veins (of systemic circulation).

(2) A tumor, varix, or a venous swelling at or inside the anal sphincter.


They arise mainly due to portal hypertension. Constipation and diarrhea can lead to hemorrhoids when there is a heightened strain during bowel movements.

Word origin: Latin haemorrhoidae; from Greek haemo, 'blood', rhein, 'flow'

Variant: hemorrhoid

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