Rectal Exam

Anatomy and Physiology

The rectum is the terminal segment of the large bowel. It is approximately 12 cm long and runs along the concavity of the sacrum. [1]

• The upper 2/3 of the anterior rectum is covered by the peritoneum.
  • In males, the anterior rectum peritoneum reflects on the surface of the bladder base.
  • In females, the anterior rectum peritoneum forms the pouch of Douglas (rectouterine pouch), which is filled with bowel loops.
• The anterior lower 1/3 of the rectum.
  • In males, anterior to the rectum lies the bladder base, prostate, and seminal vesicles
  • In females, anterior to the rectum lies the vagina, and at the fingertip, the cervix and uterus.
• The anus is 3-4 cm long and connects the rectum to the perineum.
• The anal wall and anal canal are supported by voluntary external sphincter muscles and involuntary internal anal sphincter muscles, with are essential for defecation and maintenance of continence.

Indications

This is an uncomfortable procedure for the patient. It is most often done when disease is suspected. It may also be done as part of a screening process. [2]

The examiner should explain the reasons for the procedure and obtain verbal consent. Reasons to perform the procedure include:

• Change in bowel habit
• Prostate evaluation
• Rectal bleeding
• Urinary or fecal incontinence
• A secondary approach to vaginal and cervical exam

It is, of course, useful and should be performed in patients with a GI bleed, where the practitioner can look for hemorrhoids, fissures, and gross blood.  It is also helpful in evaluating constipation, to evaluate sensation, tone, and coordination of contraction.  For fecal incontinence, again, evaluating rectal tone is essential.  

Rectal Exam in Children

This exam should be avoided; if essential, use the fifth rather than the index finger.

Rectal Exam in Elderly

Rectal examination is more often required in elderly patients because diseases affecting the bowel arise more often in elderly patients. The left lateral position may be uncomfortable. Time should be taken to achieve a comfortable position that allows examination.

Contraindications

The main contraindication to the digital rectal exam is if a patient is immunocompromised, which runs the risk of introducing infection in these patients and can be potentially life-threatening. 

Absolute

• Absence of anus
• Immunosuppressed patient
• Imperforate anus
• Prolapsed thrombosed internal hemorrhoids
• Stricture
• Severe anal pain
• Unwilling patient

Relative

• Acute abdomen
• Coagulopathy
• Major rectal trauma
• Postoperative anal surgery
• Recent acute myocardial infarction
• Valvular heart disease or prosthetic valves

Equipment

• Gloves
• Water-soluble lubricant
• Lighting
• Soft tissues

Preparation

Explain the reasons for performing the procedure to the patient. A chaperone should be present. Inform patients that the examination may be uncomfortable and they may feel the urge to defecate.

Technique or Treatment

1. Position in the left lateral position; flex the hips and knees and position the buttocks at the edge of the examining table.
2. Part the buttocks to expose the anal verge and natal cleft and inspect the skin and anal margin.
3. Lubricate the examining index finger with a water-soluble gel and then press the examining finger against the posterior anal margin (6 o'clock).
4. The finger should slip into the anal canal, and the fingertip is directed posteriorly following the sacral curve.
5. Evaluate the anal tone by asking patients to squeeze the finger with their anal muscles.
6. Move the finger through 180°, feeling the walls of the rectum.
7. Rotate the finger to the 12 o'clock position, and palpate the anterior wall. Rotation facilitates further examination of the opposing walls of the rectum.
8. In males, the prostate will be palpated anteriorly.
9. In women, the cervix and a retroverted uterus may be felt with the tip of the finger.
10. Feel the walls of the rectum throughout the 360°.
11. Exam of the prostate gland (felt anteriorly):

• Normal size is 3.5 cm wide and it should protrude about 1 cm into the lumen of the rectum.
• The prostate is normally rubbery and firm, with a smooth surface and a palpable sulcus between the left and right lobes.
• It should not be tender and there should be no nodularity.
• Massage of the prostate may reveal prostatic fluid at the urethral meatus.
• On removal of the finger, check the tip of the glove for stool color and the presence of blood.

Complications

• Discomfort and pain
• Tearing of the perianal skin
• Abrasion of hemorrhoidal tissue
• Infection and bacteremia

Clinical Significance

Rectal examination findings include:

External Inspection

• Anal fissures
• Anal fistula
• Genital warts
• External hemorrhoids
• Pilonidal sinus
• Skin disease (seborrhoeic eczema, skin cancer, natal cleft dermatitis)
• Skin tags
• Skin discoloration with Crohn disease
• Rectal prolapse

Internal Inspection

• Internal hemorrhoids
• Rectal carcinoma
• Rectal polyps
• Tenderness with prostatitis or acute appendicitis
• Malignant or inflammatory conditions of the peritoneum with anterior palpation

Enhancing Healthcare Team Outcomes

The fecal occult blood test (FOBT) has no role in the evaluation of acute gastrointestinal bleeding. The test has low specificity, and reasons for false-positive include medications, digital manipulation, diet, and more. The FOBT can be used in annual colon cancer screening, as recommended by the interprofessional taskforce.[3] A positive test may also confirm the need for endoscopic evaluation in a patient with chronic anemia. However, patients with unexplained iron deficiency anemia should already be considered for endoscopy regardless of the outcome from FOBT.