This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Internal rectal venous plexus lies at ? 
Select and explain. 
A. Outer anal verge, B. White line of Hilton, C. Proximal to pectinate line, D. Distal to pectinate line
C: Proximal to pectinate line
Answer: C: Proximal to pectinate line 
Explanation: Internal rectal venous plexus (Hemorrhoidal plexus) lies above the pectinate line.It lies in the submucosa of anal canal and drains mainly into superior rectal vein, but communicates freely with external rectal venous plexus.The internal plexus is in the form of a series of dilated pouches and veins present in the 3, 7 and 11 O'clock positions are large and constitute potential sites from primary internal piles (hemorrhoids).