What are the steps involved in a Per Rectal (PR) examination?

Steps in Performing a Digital Rectal Examination

Patient Preparation and Positioning

The patient should be positioned based on their physical condition and clinical indication, with the left lateral decubitus position being most commonly used for routine examinations. 1, 2

• Explain the procedure beforehand - patients expect and prefer to be informed about the possibility of rectal examination prior to the procedure, including the method and reason for performing it 3
• Obtain informed verbal consent - formal consent is expected by patients, though verbal consent is sufficient 3
• Have a chaperone present when logistically possible 3
• Ask the patient to empty their bladder before the examination to minimize discomfort, particularly during bimanual examination 1
• Position the patient in left lateral decubitus position with knees drawn up, or alternatively standing and leaning forward, or lithotomy position depending on clinical context 1, 2

External Inspection

• Separate the buttocks and observe the perianal area for abnormalities 1
• Inspect the perianal skin for evidence of fecal soiling, lesions, fissures, hemorrhoids, or skin changes 1, 4
• Observe perineal descent during simulated defecation (asking patient to bear down as if having a bowel movement) 1, 4
• Observe perineal elevation during squeeze maneuver (asking patient to contract as if holding back stool) 1, 4
• Test the anal reflex by light pinprick or scratch of the perianal skin 1, 4
• Look for patulous opening of the anal verge during straining, which may suggest neurogenic dysfunction 1, 4
• Check for prolapse of anorectal mucosa during bearing down 1, 4

Digital Palpation

• Lubricate the gloved examining finger with water-soluble lubricant 1
• Warn the patient before insertion - reassure them that while it may be uncomfortable, it should not be painful 1
• Apply gentle pressure to the anal sphincter and wait for relaxation before insertion 1

Assessment of Sphincter Function

• Assess resting tone of the anal sphincter immediately upon insertion 1, 4
• Evaluate augmentation with squeeze - ask the patient to squeeze as if holding back stool and assess the increase in tone 1, 4
• Palpate the puborectalis muscle above the internal sphincter, which should contract during squeeze 1, 4
• Check for tenderness along the puborectalis - acute localized tenderness suggests levator ani syndrome 1, 4

Systematic Palpation

• Sweep circumferentially around the rectal vault in all four quadrants 2
• Palpate anteriorly in males to assess the prostate (noting that the examining finger typically reaches only the posterior and lateral aspects, not the entire gland) 1, 5
• Assess rectal vault integrity - check for masses, strictures, or abnormalities 1, 6
• Check for gross blood on the examining finger 6
• Test expulsionary forces - ask the patient to "push out my finger" as if having a bowel movement 1, 4

Important Technical Considerations

The reach of the examining finger is limited to approximately 7-10 cm, meaning only a portion of pelvic structures can be palpated. 5, 2

• Maximum pressure applied during expert examination ranges up to 3.3N, with higher pressure typically applied to the prostate than rectal walls 7
• Be cautious if foreign body or sharp object is suspected - obtain imaging first before digital examination 1
• Document all findings carefully, including external appearance, sphincter tone, masses, tenderness, and any blood 1, 6

Clinical Pitfalls to Avoid

• A normal digital rectal examination does not exclude pelvic floor dysfunction - the examination has limitations in sensitivity 1, 4
• Prostate size estimation by DRE correlates poorly with actual volume and has limited accuracy for detecting prostate cancer (sensitivity 50-80%) 1, 2
• The entire prostate cannot be palpated in most cases - only 3.2% of prostates can be fully examined by DRE 5
• Hemoccult testing during rectal examination in trauma patients does not add useful information for acute management decisions 6