Hemorrhoids are dilated veins within the anal canal and distal rectum. External hemorrhoids are derived from the external hemorrhoidal plexus below the dentate line and are covered by stratified squamous epithelium. Internal hemorrhoids are derived from the internal hemorrhoidal plexus above the dentate line and are covered by rectal mucosa.
Proctitis is an inflammation of the rectal mucosa. It may be idiopathic or related to a specific cause, such as radiation or gonococcal infection.
Nearly everyone has experienced anorectal discomfort. Our low-fiber diet, which results in small, hard stools; our lifestyle, which restricts the opportunities for defecation; and our erect posture, which promotes engorgement of the hemorrhoidal plexus, all combine to make anorectal problems virtually ubiquitous.