Proper stepwise visual inspection of the perineum, anal canal, rectum, and vagina should precede any other examination. Proper lighting is essential, and various light sources are commercially available, including overhead lights, tall/gooseneck lamps on a stand, and head lamps. It should be noted that the “clockface” nomenclature is not recommended for localizing anorectal findings. This nomenclature is dependent upon the position of the patient, and hence different interpretations of the true location may differ from examiner to examiner. Rather, designation using the cardinal quadrants (i.e., left lateral, right anterior, right posterior) is commonly practiced by most colorectal surgeons.

An overall assessment of the shape of the buttock and inspection of the lower sacrococcygeal area is undertaken. Then a gentle spreading of the buttocks to gain proper exposure is undertaken. A great deal of information can be gained by visualization only, including scarring, fecal soiling, purulence, blood or mucous drainage, excoriations, erythema, anal sphincter shape, perineal body bulk, hemorrhoidal disease, skin tags, overt signs of inflammatory bowel disease, external fistulous openings, rectal prolapse (procidentia), neoplasm, and any evidence of previous anorectal surgery. Next, the patient is asked to strain (Valsalva maneuver) to help determine and assess for perineal descent, uterine/vaginal prolapse, or rectal prolapse. It should be noted that the best position to evaluate rectal prolapse is either in the squatting position or in the sitting position on the toilet or commode after an enema has been administered. The use of an illuminated handheld mirror is very useful to examine the patient while in the sitting position to diagnose prolapse and other anorectal pathology [1].

Gentle and directed palpation of the anorectal region also gives the examiner a great detail of information. Gently touching the anal verge will elicit the anocutaneous reflex (anal wink) which is indicative of an intact pudendal nerve. Additionally, gentle spreading of the anus will help elicit an anal fissure or ulceration. Palpation of the anal margin/gluteal region can help identify an abscess, external opening of a fistulous tract, or possibly a mass.

T he digital rectal examination (DRE) is a simple and well-tolerated procedure that should be performed in almost every patient who presents for an anorectal condition/complaint. A well-performed DRE will provide information regarding the contents and potential pathology of the anal canal, distal rectum, and adjacent organs. DRE may also permit an assessment of the neurological function of the muscles of fecal continence. Relative contraindications to performing a DRE are usually related to pain at the anal opening and include an acute or chronic anal fissure, thrombosed hemorrhoids, or grade IV internal hemorrhoids. The keys to a successful DRE can be summarized by simple rules: adequate lubrication, gentleness, and attention to detail [2].

After proper communication with the patient, a well-lubricated index finger is placed across the anus and the tip is gently inserted into the anal opening. Lubrication should be warmed if possible, and lidocaine jelly should also be available. If the patient’s response is an involuntary spasm of the internal sphincter, the examiner should withdraw their fingertip and gently try again. Ask the patient to bear down as if to pass stool. This maneuver will cause relaxation of the entire sphincter complex and should facilitate an easy insertion [3]. The finger should be gradually and slowly advanced. The distal rectum and anal canal along with surrounding structures should be investigated in an organized and stepwise fashion. Resting anal tone followed by squeeze tone should be assessed. Assessment should be made of the entire circumference of the lumen by gently sweeping around the entire anus and distal rectum. Anteriorly in a male, the prostate should be palpated and assessed for nodularity, hypertrophy, and firmness. In the female, anteriorly feel for a rectocele and the cervix and uterus (if present) can also be palpated. Posteriorly, the presence of a presacral (retrorectal) mass may be palpated. Bimanual inspection may be necessary when examining a female patient in order to palpate the rectovaginal septum and associated vaginal/adnexal structures. Redundant rectal mucosa may be palpated as well as any stricturing or narrowing. Induration or a fibrous cord, representing an internal fistulous opening, may also be felt on DRE. Exclusion of any masses should be carefully performed. The patient should be asked to perform a Valsalva maneuver to potentially bring any lesions of the upper rectum/rectosigmoid into the examiners reach. If a mass is felt, its size, position, characteristics (sessile, polypoid, ulcerated), mobility (mobile, tethered, fixed), and relationship to other structures (distance from the anal verge, distance from the anorectal ring) must be accurately recorded.

The levator ani/puborectalis muscles can also be assessed on DRE with evaluation of both the strength and function of these muscles, along with any tenderness on direct palpation, indicating a possible pelvic pain disorder. When a patient with good sphincter function is asked to squeeze these muscles, the examiners finger will feel the muscle tighten and will have his finger pulled up into the rectum. Additionally, when the examiner pulls posteriorly on these muscles, the anal opening should gape and then return to normal, representing an intact reflex pathway to the thoracolumbar spinal cord.

The anorectal examination in most cases should be followed with an endoscopic investigation to complete the work-up. This may include anoscopy, proctosigmoidoscopy, and flexible endoscopy. All three are typically performed in the clinic setting without sedation or mechanical bowel preparation and are tolerated quite well by the patient.