Rosette of internal hemroids 

Rectum & Anal Canal
The rectum (‘rectum’ means ‘straight’) and the anus form the last part of the digestive system. The rectum is a small, straight muscular tube approx. 5 inches long, which forms the lowest part of the large intestine. It acts as a reservoir for the stool. The stool finally passes through the anal canal and is expelled from the body through an opening called the anus. The anal canal consists of 2 sphincters (muscular valves): internal sphincter and an external sphincter. Both of these sphincters help to keep the stool in the rectum till they can be eliminated, during which process these sphincters open up and allow the passage of stools.