The Examination Of The Anus Jennifer Browne

THE ANATOMY AND PHYSIOLOGY OF THE RECTUM AND ANUS

The rectum turns downwards and backwards from the recto-sigmoid junction to follow the curve of the sacrum. It passes out of the peritoneal cavity to end 2 cm in front of and below the tip of the coccyx at its junction with the anal canal. The rectum is totally sheathed in longitudinal muscle fibres. The col-orectum is lined with columnar epithelium as far as the dentate line in the middle of the anal canal, where sensitive squamous epithelium, in continuity with that of the perineal skin, takes over. In normal subjects there is a 60-105 degree angle between the rectum and the anal canal. The angle is maintained by the puborectalis muscle, which passes backwards from the pubis around the anorectal junction and back to the pubis, so pulling the anorectal junction forwards (Martini, 2004).

The anorectal junction is not a discrete point, but a region of longitudinal mucosal folds extending superiorly from a zone of mucosa that is paler and flatter. This gives the appearance of a horizontal band with teeth: hence the term 'pectinate line'. The mucosal ridges forming the tooth-like character of the line are termed anal folds or columns. At the pectinate line between the base of the anal columns, the muscosa is redundant, and outpockets to form the anal crypt. The epithelium of the anus, i.e., distal to the pectinate line, is characterised by stratified squamous cells of the non-keratinising type (Martini, 2004).

The anal canal is slightly shorter in women than in men (4.6cm vs. 3.7cm). Two cylinders of muscle, the internal anal sphincter, which consists of smooth muscle and is responsible for 80 per cent of the resting tone, and the external anal sphincter, surround it. The external sphincter works in harmony with the puborectalis and levator ani of the pelvic floor (Martini, 2004).

Advanced Clinical Skills for GU Nurses. Edited by Matthew Grundy-Bowers and Jonathan Davies © 2007 John Wiley & Sons Ltd

EXAMINATION OF THE ANUS

Examination of the anus and rectum should only be carried out on those complaining of anal rectal symptoms, those who have receptive anal sex or receptive oro-anal sex, known as rimming, and those having receptive anal use of sex toys or receptive digital anal penetration. A detailed history is important and will provide clues to the diagnosis. All genital examinations should be carried out with tact and sensitivity, and conducted in a thorough and professional manner. Full explanation of the procedure should be carried out prior to examination, to allay patients' fears and for consent from the patient obtained (Walsh et al., 1999).

An examination should only take place in a private area/room that can be secured to prevent entry to the room during the examination. Good lighting and the use of gloves is essential. Gloves are not only important because of universal precautions but also to re-enforce the clinical nature of the examination (Epstein et al., 2000). All patients should be offered a chaperone when having an intimate examination (Epstein et al., 2000). It is good practice to have a chaperone present for professional and legal reasons. If a patient declines to have a chaperone present this should be documented in the clinical notes. If the clinician feels uncomfortable carrying out an intimate examination without a chaperone, the clinician can refuse to examine the patient.

The patient after explanation of the procedure should be given privacy to undress and a blanket, cover or gown to maintain dignity. Patients should be placed in the left lateral position. With good lighting, firstly inspect the anal skin.

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