Anorectal diseases
Summary
This chapter provides a visual review of anorectal anatomy, functions, and pathologies. It begins with a coronal section of the anorectum, which highlights the orientation of the anal sphincters and pelvic floor muscles. Because symptomatic internal hemorrhoids are one of the most common lesions seen by the practicing gastroenterologist, the chapter shows a photograph of the simplest, most widely used instrument for management of internal hemorrhoids, the Barron-type rubber band ligator with its ancillary equipment. It also shows examples of carcinoma of the anus. One fairly subtle lesion is Bowen disease (cutaneous squamous cell carcinoma in situ), which may be confused with the anal lesions of dermatitis and psoriasis.