This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: Anatomy
Bleeding vessel in hemorrhoids is (FMGE Dec 2018) 
Select and explain. 
A. Superior rectal aery, B. Superior rectal vein, C. Middle rectal aery, D. Middle rectal vein
B: Superior rectal vein
Answer: B: Superior rectal vein 
Explanation: 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.