Anatomy of the anal canal with attention to the clinical management of symptomatic hemorrhoids

Hemorrhoids are normal anatomic structures that aid in the maintenance of fecal continence. The name hemorrhoid includes structures proximal and distal to the anal canal. These structures can manifest a variety of conditions resulting in pruritus, pain, bleeding, and mucous discharge. The anatomy of the anal canal is reviewed with emphasis on structures and relationships that bear on the clinical management of symptomatic hemorrhoidal disease. A brief history of the knowledge of anal anatomy is presented. The relationship of the vascular cushions, the surrounding structures, and their innervation that allows our current management is reviewed in detail.