The following two figures demonstrate the structures of the rectum-anus-skin junction.

Clinical Case

A 50-year old man presents with a chronic prolapsed enlarged hemorrhoid through his anus. He complains that it bleeds profusely after defecation and he experiences discomfort. Which is what eventually brings him to his doctor. What are the two plexuses that are found in the rectum and anus? In which layers are they found histologically? Which layers are found between the lumen and the plexuses? How does the epithelium change from the rectum to the anus? What happens to the muscle layers at the rectum-anal junction? What types of muscle are present in the rectum and anus?

Microscopy

A very low magnification of the rectum-anus-skin junction demonstrating the rectum-anus transition. Fig 45-001

A very low magnification of the rectum-anus-skin junction demonstrating the anus-skin transition. Fig 45-002

Memorandum
Clinical Case	Fig 45-001	Fig 45-002