ABSTRACT
PRURITUS ANI Anatomy The anal and perianal skin, which is extremely sensitive, is richly supplied with sensory nerve endings in a pattern similar to that of the lips, fingers, and genitalia [1]. The cutaneous sensation experienced in the perianal region and lining of the anal canal below the dentate line is conducted through afferent fibers contained in the inferior rectal nerves, branches of the pudendal nerves bilaterally. The pudendal nerves arise from dorsal sacral nerve roots of S2-4. As the pudendal nerves leave the pelvis bilaterally, they cross the ischial spine and continue in the ischioanal fossa thru Alcock’s canal. Other important branches include the perineal nerves to the urinary sphincter and the dorsal nerves to the penis or clitoris.
