Anorectal Examination Essay

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ANORECTAL EXAMINATION SUBMITTED BY: PRATEEK BAGI CONTENTS ANATOMY AND PHYSIOLOGY The gastrointestinal tract terminates in a short segment, the anal canal. Its external margin is poorly demarcated, but generally the skin of the anal canal can be distinguished from the surrounding perianal skin by its moist, hairless appearance. The anal canal is normally held in a closed position by action of the voluntary external muscular sphincter and the involuntary internal sphincter, the latter an extension of the muscular coat of the rectal wall. The direction of the anal canal on a line roughly between anus and umbilicus should be carefully noted. Unlike the rectum above it, the canal is liberally supplied by somatic sensory nerves, so that a poorly directed finger or instrument will produce pain. The rectum begins at the termination of the sigmoid colon about 12 cm from the anal verge .Two muscle bundles, known as the internal and external anal sphincters, participate in defecation. The internal anal sphincter is an enlargement of the circular smooth muscle of the colon and functions involuntarily. The external anal sphincter consists of striated muscle bands under the voluntary control of the puborectalis muscle. The rectum has the same innervation as the bladder; the hypogastric nerves innervate the internal anal sphincter, and the internal pudendal nerve (S3–S4) operates the external anal sphincter. Because of the common innervation, dysuria is a common complaint associated with rectal disorders. Diagramatic representation of anorectal junction An important landmark both anatomically and clinically is the pectinate line where the anus and rectum merge, approximately 3 to 4 cm from the skin. It serves as a demarcation for venous and lymphatic drainage and for the nerve supply. Above the pectinate line,

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