Although a very common abnormality, its prevalence probably is underestimated due to the many asymptomatic patients. Symptoms present as nonspecific, indicating that a directed history and a thorough examination, including an anoscopy when necessary, are essential in guiding the physician to the appropriate diagnosis and management. The usual course is acute, chronic, or relapsing. Internal, external, and mixed hemorrhoids are differentiated by their anatomical origin in the anal canal. External hemorrhoids arise below the dentate line ectoderm and are covered by stratified squamous epithelium with innervation by the inferior rectal nerve.
Mixed hemorrhoids are confluent internal and external hemorrhoids.
Anastomoses exist between all 3 veins. Hemorrhoids are dilated arteriovenous complexes. Although many theories exist regarding the unclear pathophysiology of hemorrhoids, the vascular cushion theory has the most acceptance. These vascular cushions, found at the anorectal junction above the dentate line, are anatomically normal. The vascular cushions present in adults, in children, and even in the embryo.