Normal Findings on Digital Rectal Examination
A normal digital rectal examination reveals normal sphincter tone at rest and with squeeze, no tenderness, no masses, and appropriate perineal sensation with intact anal reflex. 1
Key Components of a Normal Rectal Examination
External Examination
- Normal perianal skin without evidence of fecal soiling, lesions, or abnormalities 1
- Intact anal reflex when tested with light pinprick or scratch 1
- No patulous opening of the anal verge during simulated defecation 1
- No prolapse of anorectal mucosa during straining 1
Digital Examination
- Normal resting tone of the anal sphincter segment 1
- Appropriate augmentation of sphincter tone with squeezing effort 1
- Normal puborectalis muscle that contracts during squeeze 1
- No localized tenderness to palpation along the puborectalis muscle (which would suggest levator ani syndrome) 1
- Normal ability to integrate expulsionary forces when asked to "expel my finger" 1
- No palpable masses or abnormalities 1
- No blood on the examining glove 2
Functional Assessment
- Normal perineal descent during simulated evacuation 1
- Normal elevation during squeeze aimed at retention 1
- Ability to relax the pelvic floor muscles during simulated defecation 1
- Coordinated function between abdominal pressure and anal relaxation during attempted defecation 3
Clinical Significance
- A normal digital rectal examination is useful in ruling out many conditions but does not completely exclude pelvic floor dysfunction 1
- Less than two findings of dyssynergia in a digital rectal exam has high sensitivity (83.2%) for ruling out rectal evacuation disorders 3
- The ability to correctly identify normal anal tone is limited (approximately 64% accuracy among physicians), making the squeeze test potentially more valuable 4
Important Caveats
- A normal examination does not exclude all pathology, particularly early or subtle conditions 1
- The assessment of anal tone is subjective and has limited accuracy even among trained physicians 4
- In trauma patients, a normal rectal examination rarely influences management decisions unless there are specific indications such as penetrating injuries near the lower gastrointestinal tract, suspected spinal cord damage, or severe pelvic fractures 2
- Digital rectal examination should be performed carefully and possibly after obtaining imaging if there is suspicion of sharp objects or foreign bodies 1
Clinical Context
- Digital rectal examination is an essential component of evaluation for various conditions including constipation, fecal incontinence, rectal bleeding, and suspected cauda equina syndrome 1
- It provides valuable information about the integrity and function of the anal sphincter and pelvic floor muscles 1
- A normal examination in conjunction with other clinical findings helps guide further diagnostic testing and management decisions 1