The structure of the anal canal was examined in histology slides. Hemorrhoids are normal features of the human anatomy. They
are pads that bulge into the lumen. Hemorrhoids have three parts: 1) the lining, which can be mucosa or anoderm; 2) the stroma
with blood vessels, smooth muscle, and supporting connective tissue; and 3) the anchoring connective tissue system, which
secures the hemorrhoids to the internal sphincter and the conjoined longitudinal coat. The anchoring and supporting connective
tissue system deteriorates with aging. The hemorrhoids not only bulge, but descend into the lumen. This becomes observable
in the third decade of life, with individual differences. The veins become distended as they lose their support. The descended
loose lining becomes more sensitive to pressure from straining and to trauma from the stool. There can be a stasis in the
veins, with clot formations and swelling or erosions of the lining, with bleeding. The hemorrhoids become symptomatic.
Key words Hemorrhoids - Etiology of hemorrhoids - Pathogenesis of hemorrhoids
Read at the meeting of the American Society of Colon and Rectal Surgeons, San Francisco, California, May 2 to 6, 1982.