Bleeding vessel in hemorrhoids is (FMGE Dec 2018)
Blood of hemorrhoids is from vein > Aery > sinusoids. Hemorrhoids - engorgement of venous plexus at / inside anal sphincter. It has slight genetic predisposition, but obesity, straining during bowel movements, sedentary life- style can predispose to them. Symptoms -irritation, pain, swelling. External hemorrhoids: Hemorrhoids occurring at anal verge (distal boundary of anal canal below pectinate line) Normally have low tendency to bleed on straining at stool. Bleeding comes from inferior rectal vein. Internal hemorrhoids: Occur inside the rectum (above pectinate line) have high tendency to bleed. Bleeding from "superior rectal vein" Prolapsed hemorrhoids are internal hemorrhoids that pass outside anal canal & form lump, which may undergo thrombosis & become painful.
Superior rectal aery
Superior rectal vein
Middle rectal aery
Middle rectal vein
FMGE 2018