3.8 Rectal Examination

Rectal Examination

Quick Answer: The rectal examination is indicated when evaluating suspected cauda equina syndrome (assessing perianal sensation and sphincter tone), unexplained gastrointestinal bleeding (fecal occult blood testing), or prostate complaints in male patients; chiropractors rarely perform the exam themselves but must recognize these indications immediately, because a positive cauda equina finding is a surgical emergency requiring immediate referral.

What the Rectal Examination Assesses

A digital rectal examination evaluates several distinct findings, each relevant to a different clinical question:

• Sphincter tone — the resting tightness of the anal sphincter around the examining finger, and the patient's ability to voluntarily contract it
• Perianal and perineal sensation — light touch and pinprick sensation over the S2 through S4 dermatomes surrounding the anus
• The anal wink (bulbocavernosus) reflex — a reflexive contraction of the anal sphincter in response to a light stroke or pinprick near the anus, testing the integrity of the S2 through S4 reflex arc
• Prostate size, symmetry, and consistency in male patients — a smooth, symmetric, mildly enlarged gland suggests benign prostatic hyperplasia, while a hard, nodular, or asymmetric gland raises concern for malignancy, and a tender, warm, boggy gland suggests prostatitis
• Occult blood in stool, tested with a fecal occult blood test on a stool sample obtained during the exam

Sphincter tone is typically graded on a simple qualitative scale — normal, reduced, or absent — based on the resistance felt around the examining finger at rest and the strength of voluntary contraction when the patient is asked to squeeze. A patient who cannot voluntarily contract the sphincter at all, in the setting of severe low back pain, is treated with the same urgency as any other cauda equina red flag. As with the breast, axilla, and urogenital examinations, informed consent, a chaperone, and thorough documentation of indication, findings, and referral are expected whenever this region is examined or when the indication for examination is identified and referred onward.

Indication One: Cauda Equina Syndrome

Cauda equina syndrome is the most urgent reason a rectal exam appears on Part III. It results from severe compression of the lumbosacral nerve roots below the level of the spinal cord, most often from a large central disc herniation, and it is a surgical emergency: delayed recognition risks permanent bowel, bladder, and sexual dysfunction along with lower-extremity paralysis.

Any combination of these findings in a patient with severe low back pain is treated as cauda equina syndrome until proven otherwise: refer immediately for emergency evaluation, emergent MRI, and likely surgical decompression. This is not a finding to monitor over subsequent visits.

Indication Two: Occult Gastrointestinal Bleeding

A fecal occult blood test is indicated when unexplained anemia, dark or tarry stools (melena), or a clinical picture suggesting gastrointestinal bleeding accompanies a patient's presentation — for example, a patient with back pain who also reports fatigue and unusually dark stool deserves consideration of an occult bleed, since retroperitoneal conditions such as a penetrating peptic ulcer can produce both back pain and gastrointestinal blood loss. A positive occult blood test warrants referral for gastroenterologic evaluation rather than chiropractic workup.

Indication Three: Prostate Evaluation

In male patients, particularly those over roughly fifty years of age or with urinary symptoms (hesitancy, retention, nocturia, weak stream) or unexplained low back or pelvic pain, prostate evaluation helps distinguish benign prostatic hyperplasia, prostatitis, and prostate malignancy. Findings that raise concern for malignancy — a hard, nodular, fixed, or asymmetric gland — warrant urologic referral for further workup, which typically includes prostate-specific antigen testing and possibly biopsy. A tender, warm, boggy prostate with acute urinary symptoms and possible fever suggests acute bacterial prostatitis; in this scenario, vigorous prostatic massage or examination is avoided because it can theoretically provoke bacteremia, and the patient is instead referred promptly for antibiotic treatment.

Documentation and the Referral Decision

Because chiropractors so rarely perform the rectal examination directly, the testable skill on Part III is almost entirely about recognizing the indication, documenting the reasoning, and choosing the correct urgency of referral. A well-documented encounter states the indication for considering the exam, the findings from history and the rest of the physical and neurological examination that support or lower suspicion for each of the three indications above, and the specific referral made (emergency department, urology, gastroenterology, or primary care) with its urgency. This documentation protects the patient through timely care and protects the practitioner by demonstrating that red flags were recognized and acted upon rather than overlooked.

When the Exam Is Required Versus Referred

In routine chiropractic practice, the digital rectal examination itself is almost always referred out rather than performed in-office. What chiropractors are responsible for is recognition and timing:

• Cauda equina red flags identified during history or neurological exam — refer immediately as an emergency; do not wait for a rectal exam to be performed before initiating referral, since the surrounding clinical picture (saddle anesthesia, bladder dysfunction, bilateral findings) already establishes the emergency
• Occult blood or unexplained gastrointestinal bleeding suspicion — refer on an urgent but non-emergent basis to gastroenterology or primary care
• Routine age-appropriate prostate screening — refer on a routine basis to the patient's primary care provider or urologist
• Prostate findings with malignancy features, or bleeding with unexplained weight loss — refer urgently rather than routinely

On Part III, the correct answer to a rectal-exam scenario question is almost always the referral decision and its urgency, not the technical performance of the exam itself.