Examination of the anus and rectum may be performed as part of a routine health visit. In patients with a prostate, examination may include the prostate. Examination of these structures is also performed when the patient has a specific concern.
- 1.
Inspect the sacrococcygeal and perianal area for:
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Skin characteristics
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Lesions
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Pilonidal dimpling and/or tufts of hair
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Inflammation
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Excoriation
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- 2.
Inspect the anus for:
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Skin characteristics and tags
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Lesions, fissures, hemorrhoids, or polyps
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Fistulae
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Prolapse
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- 3.
Insert finger and assess sphincter tone
- 4.
Palpate the muscular ring for smoothness and evenness of pressure against examining finger
- 5.
Palpate the lateral, posterior, and anterior rectal walls for:
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Nodules, masses, or polyps
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Tenderness
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Irregularities
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- 6.
In patients with a prostate, palpate the posterior surface of the prostate gland through the anterior rectal wall for:
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Size
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Contour
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Consistency
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Mobility
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- 7.
In patients with a uterus, palpate the cervix and uterus through the anterior rectal wall for:
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Size
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Shape
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Position
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Smoothness
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Mobility
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- 8.
Have the patient bear down, and palpate deeper for tenderness and nodules
- 9.
Withdraw the finger and examine fecal material for
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Color
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Consistency
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Blood or pus
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Occult blood by chemical test if indicated
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Anatomy and Physiology
The rectum and anus form the terminal portions of the gastrointestinal (GI) tract ( Fig. 21.1 ). The anal canal is approximately 2.5 to 4 cm long and opens onto the perineum. The tissue visible at the external margin of the anus is moist, hairless mucosa. Juncture with the perianal skin is characterized by increased pigmentation and, in the adult, the presence of hair.
The anal canal is normally kept securely closed by concentric rings of muscle, the internal and external sphincters. The internal ring of smooth muscle is under involuntary autonomic control. The urge to defecate occurs when the rectum fills with feces, which causes reflexive stimulation that relaxes the internal sphincter. Defecation is controlled by the striated external sphincter, which is under voluntary control. The lower half of the canal is supplied with somatic sensory nerves, making it sensitive to painful stimuli, whereas the upper half is under autonomic control and is relatively insensitive. Therefore conditions of the lower anus may cause pain, whereas those of the upper anus will usually not.
Internally the anal canal is lined by columns of mucosal tissue (columns of Morgagni) that fuse to form the anorectal junction. The spaces between the columns are called crypts, into which anal glands empty. Inflammation of the crypts can result in fistula or fissure formation. Anastomosing veins cross the columns, forming a ring called the zona hemorrhoidalis. Internal hemorrhoids result from dilation of these veins. The lower segment of the anal canal contains a venous plexus that drains into the inferior rectal veins. Dilation of this plexus results in external hemorrhoids.
The rectum lies superior to the anus and is approximately 12 cm long. Its proximal end is continuous with the sigmoid colon. The distal end, the anorectal junction, is visible on proctoscopic examination as a sawtooth-like edge, but it is not palpable. Above the anorectal junction, the rectum dilates and turns posteriorly into the hollow of the coccyx and sacrum, forming the rectal ampulla, which stores flatus and feces. The rectal wall contains three semilunar transverse folds (Houston valves). The lowest of these folds can be palpated by the examiner.
The prostate gland is located at the base of the bladder and surrounds the urethra. It is composed of muscular and glandular tissue and is approximately 4 × 3 × 2 cm. The posterior surface of the prostate gland is in close contact with the anterior rectal wall and is accessible by digital examination. It is convex and divided by a shallow median sulcus into right and left lateral lobes. A third or median lobe, not palpable on examination, is composed of glandular tissue and lies between the ejaculatory duct and the urethra. It contains active secretory alveoli that contribute to ejaculatory fluid. The seminal vesicles extend outward from the prostate ( Fig. 21.2 ).
The vagina lies in contact with the anterior rectal wall of the rectum and is separated from it by the rectovaginal septum. See Chapter 19 for a more detailed discussion.
Infants and Children
At 7 weeks of gestation, a portion of the caudal hindgut is divided by an anorectal septum into a urogenital sinus and a rectum. The urogenital sinus is covered by a membrane that develops into the anal opening by 8 weeks of gestation. Most anorectal malformations result from abnormalities in this partitioning process.
The first meconium stool is ordinarily passed within the first 24 after birth and indicates anal patency. It is common for newborns, especially those who are breast-fed, to have a stool after each feeding (the gastrocolic reflex). Both the internal and external sphincters are under involuntary reflexive control as myelination of the spinal cord is incomplete.
By the end of the first year, the infant may have one or two bowel movements daily. Children are developmentally ready to begin toilet training between 2 and 4 years of age. Girls typically acquire bladder control before boys; bowel control typically is achieved before bladder control ( Elder, 2016 ).
The prostate is small, inactive, and not palpable on rectal examination. The prostate remains undeveloped until puberty, at which time androgenic influences prompt its growth and maturation. The initially minimal glandular component develops active secretory alveoli, and the prostate becomes functional.
Pregnant Patients
During pregnancy, pressure increases in the veins below the enlarged uterus. Dietary habits and hormonal changes that decrease gastrointestinal tract tone and motility produce constipation. These factors predispose pregnant individuals to the development of hemorrhoids. Labor, which results in pressure on the pelvic floor by the presenting part of the fetus and expulsive efforts of the pregnant patient, may also aggravate the condition, causing protrusion and inflammation of hemorrhoids.
Older Adults
Degeneration of afferent neurons in the rectal wall interferes with the process of relaxation of the internal sphincter in response to distention of the rectum. As a result, the older adult may have a higher pressure threshold for the sensation of rectal distention with consequent retention of stool. Conversely, as the autonomically controlled internal sphincter loses tone, the external sphincter, by itself, cannot control the bowels, and the older adult may experience fecal incontinence.
The fibromuscular structures of the prostate gland atrophy, with loss of function of the secretory alveoli; however, the atrophy of aging is often obscured by benign hyperplasia of the glandular tissue. The muscular component of the prostate is progressively replaced by collagen.
Review of Related History
For each of the symptoms or conditions discussed in this section, targeted topics to include in the history of the present illness are listed. Responses to questions about these topics provide clues for focusing the physical examination and the development of an appropriate diagnostic evaluation. Questions regarding medication use (prescription and over-the-counter preparations) as well as complementary and alternative therapies are relevant for each.
History of Present Illness
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Changes in bowel function
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Character: number, frequency, consistency of stools; presence of mucus or blood; color (dark, bright red, black, light, or clay-colored); odor
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Onset and duration: sudden or gradual, relation to dietary change, relation to stressful events
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Accompanying symptoms: incontinence, flatus, pain, fever, nausea, vomiting, cramping, abdominal distention
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Medications: iron, laxatives, stool softeners
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Anal discomfort: itching, pain, stinging, burning
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Relation to body position and defecation
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Straining at stool
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Presence of mucus or blood
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Interference with activities of daily living or sleep
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Medications: hemorrhoid preparations
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Rectal bleeding
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Color: bright or dark red, black
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Relation to defecation
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Amount: spotting on toilet paper versus active bleeding
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Accompanying changes in stool: color, frequency, consistency, shape, odor, presence of mucus
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Associated symptoms: incontinence, flatus, rectal pain, abdominal pain or cramping, abdominal distention, weight loss
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Medications: iron, fiber additives
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Changes in urinary function in patients with a prostate
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History of enlarged prostate or prostatitis
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Symptoms: hesitancy, urgency, nocturia, dysuria, change in force or caliber of stream, dribbling, urethral discharge
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Medications: antihistamines, anticholinergics, tricyclic antidepressants, 5-alpha-reductase inhibitors
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Past Medical History
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Gender identity: female, male, transgender woman, transgender man; gender assigned at birth
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Hemorrhoids
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Spinal cord injury
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Bowel habits and characteristics: timing, frequency, number, consistency, shape, color, odor
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Males and transgender women: prostatic hypertrophy or carcinoma
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Females and transgender men: episiotomy or fourth-degree laceration during delivery
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Colorectal cancer or related cancers: breast, ovarian, endometrial
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Anal, rectal, prostate surgeries
Family History
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Rectal polyps
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Colon cancer or familial cancer syndromes (see Risk Factors box, Chapter 18 )
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Prostate cancer (see Risk Factors box)
Personal and Social History
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Travel history: areas with high incidence of parasitic infestation, including zones in the United States
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Diet: inclusion of fiber foods (cereals, breads, nuts, fruits, vegetables) and concentrated high-fiber foods; amount of animal fat
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Risk factors for colorectal, prostate, or anal cancer (see Risk Factors Box in Chapter 18 )
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High-risk sexual practices for anal HPV infection (see Patient Safety, “Sexually Transmitted Infections” and Box 21.1 )
Box 21.1
From CDC, 2015.
Screening for Sexually Transmitted Infections in Special Populations
The Centers for Disease Control and Prevention (CDC) has identified populations who are at risk for sexually transmitted infections based on sexual practices or, in the case of fetuses, are at risk for debilitating effects of intrauterine or perinatally transmitted infections. Adolescents, persons in correctional facilities, men who have sex with men, women who have sex with women, and transgender men and women may engage in practices that expose them to a variety of sexually transmitted diseases. The CDC has specific screening and prevention recommendations for each group which are available at http://www.cdc.gov (CDC STD Treatment Guidelines)
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Vaccination status for the human papilloma virus (HPV)
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Use of alcohol
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Age: Older than 50 years
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Race:/ethnicity: more common in African Americans and in Caribbean patients of African ancestry; less common in Asian American and Hispanic/Latinos than in non-Hispanic whites
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Geography: common in North America and northwestern Europe, Australia, and on Caribbean islands; less common in Asia, Africa, Central America, and South America
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Family history of prostate cancer: twice the risk with one first-degree relative; risk increases with more than one first-degree relative
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Inherited cancer syndromes: BRCA1, BRCA2 mutations; hereditary nonpolyposis colorectal cancer
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Gonadectomy in transgender women does not decrease the risk of prostate cancer
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Infection with high-risk type HPV
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HPV-related conditions: anal warts, cervical cancer
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Multiple sexual partners
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Receptive anal intercourse
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Cigarette smoking
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Immunosuppression: HIV infection
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Gender/ethnicity: more common in women than men except in African Americans, in whom it is more common in men than in women.
Infants and Children
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Newborns: characteristics of stool
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Bowel movements accompanied by crying, straining, bleeding
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Feeding habits: types of foods, milk (formula or breast for infants), appetite
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Age at which bowel control and toilet training were achieved
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Encopresis (involuntary “fecal soiling” in children who have usually already been toilet-trained)
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Associated symptoms: episodes of diarrhea or constipation; tenderness when cleaning after a stool; perianal irritations; weight loss; abdominal pain, nausea, vomiting
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Congenital anomaly: imperforate anus, myelomeningocele, aganglionic megacolon
Pregnant Patients
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Weeks of gestation and estimated date of delivery
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Exercise
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Fluid intake and dietary habits
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Medications: prenatal vitamins, iron, fiber supplements
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Use of complementary or alternative therapies
Older Adults
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Changes in bowel habits or character: frequency, number, color, consistency, shape, odor
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Associated symptoms: weight loss, rectal or abdominal pain, incontinence, flatus, episodes of constipation or diarrhea, abdominal distention, rectal bleeding
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Dietary changes: intolerance for certain foods, inclusion of high-fiber foods, regularity of eating habits, appetite
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History of enlarged prostate, urinary symptoms (hesitancy, urgency, nocturia, dysuria, force and caliber of urinary stream, dribbling)
Examination and Findings
Equipment
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Gloves
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Water-soluble lubricant
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Drapes
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Penlight or other light source
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Fecal occult blood testing materials if indicated
Preparation
Although the rectal examination is generally uncomfortable and sometimes embarrassing for the patient, it provides important information that is a necessary part of a comprehensive examination. Be calm, slowly paced, and gentle in your touch. Explain what will happen step by step and let the patient know what to expect. A hurried or rough examination can cause unnecessary pain and sphincter spasm, and you can easily lose the trust and cooperation of the patient.
The patient with a really acute rectal problem will often shift uncomfortably from side to side when sitting.
Positioning
The rectal examination can be performed with the patient in any of these positions: knee-chest; lithotomy; left lateral with hips and knees flexed; or standing with the hips flexed and the upper body supported by the examining table. In adult males, the latter two positions are satisfactory for most purposes and allow adequate visualization of the perianal and sacrococcygeal areas. In women, the rectal examination is most often performed as part of the rectovaginal examination while the patient is in the lithotomy position (see Chapter 19 ). Transgender women and men should be examined in the position of their identified gender.
Ask the patient to assume one of the examining positions, guiding gently with your hands when necessary. Use drapes but retain good visualization of the area. Glove one or both hands.
Sacrococcygeal and Perianal Areas
Inspect the sacrococcygeal (pilonidal) and perianal areas. The skin should be smooth and uninterrupted. Inspect for lumps, rashes, inflammation, excoriation, scars, pilonidal dimpling, and tufts of hair at the pilonidal area. Fungal infection and pinworm infestation can cause perianal irritation. Fungal infection is more common in adults with diabetes, and pinworms are more common in children. The best time to visualize pinworms in children is after they fall asleep. Inspection of the anus often reveals them. Palpate the area. The discovery of tenderness and inflammation should alert you to the possibility of a perianal abscess, anorectal fistula or fissure, pilonidal cyst, or pruritus ani.
Anus
Spread the patient’s buttocks apart and inspect the anus. Use a penlight or lamp to assist in visualization. The skin around the anus will appear coarser and more darkly pigmented. Look for skin lesions, skin tags or warts, external hemorrhoids, fissures, and fistulae. Ask the patient to bear down. This will make fistulae, fissures, rectal prolapse, polyps, and internal hemorrhoids more readily apparent.
Sphincter
Lubricate your index finger of your gloved hand and press the pad of it against the anal opening ( Fig. 21.3, A ). Ask the patient to bear down to relax the external sphincter. As relaxation occurs, slip the tip of the finger into the anal canal (see Fig. 21.3, B ). Warn the patient that there may be a feeling of urgency for a bowel movement, and assure him or her that this will not happen. Ask the patient to tighten the external sphincter around your finger ( Fig. 21.4, A ), noting its tone; it should tighten evenly with no discomfort to the patient. A lax sphincter may indicate neurologic deficit or sexual abuse. An extremely tight sphincter can result from scarring, spasticity caused by a fissure or other lesion, inflammation, or anxiety about the examination.
An anal fistula or fissure may produce such extreme tenderness that you are not able to complete the examination without local anesthesia. Rectal pain is almost always indicative of a local disease. Look for irritation, rock-hard constipation, rectal fissures, fluctuance from a perirectal abscess, or thrombosed hemorrhoids. Always inquire about previous episodes of pain.
Anal Ring
Rotate your finger to examine the muscular anal ring ( Fig. 21.4, B ). It should feel smooth and exert even pressure on the finger. Note any nodules or irregularities.
Lateral and Posterior Rectal Walls
Insert your finger farther and palpate in sequence the lateral and posterior rectal walls, noting any nodules, masses, irregularities, polyps, or tenderness ( Fig. 21.4, C ). The walls should feel smooth, even, and uninterrupted. Internal hemorrhoids are not ordinarily felt unless they are thrombosed. The examining finger can palpate a distance of about 6 to 10 cm into the rectum.
Bidigital Palpation
Bidigital palpation with the thumb and index finger can sometimes reveal more information than palpating with the index finger alone. To perform bidigital palpation, gently press your thumb against the perianal tissue and bring your index finger toward the thumb. This technique is particularly useful for detecting a perianal abscess.
Anterior Rectal Wall
Rotate the index finger to palpate the anterior rectal wall as above. Ask the patient to bear down. This allows you to reach a few centimeters farther into the rectum. Because the anterior rectal wall is in contact with the peritoneum, you may be able to detect the tenderness of peritoneal inflammation and the nodularity of peritoneal metastases. The nodules, called shelf lesions, are palpable in the peritoneal cul-de-sac. These can be felt as a hard, nodular shelf at the tip of the examining finger.
Prostate
You can palpate the posterior surface of the prostate gland ( Fig. 21.5 ) on the anterior wall. The patient that may feel the urge to urinate, but assure the patient it will happen. Note the size, contour, consistency, and mobility of the prostate. The gland should feel like a pencil eraser—firm, smooth, and slightly movable—and it should be nontender. A healthy prostate has a diameter of about 4 cm, with less than 1 cm protrusion into the rectum. Greater protrusion denotes prostatic enlargement, which should be noted with the amount of protrusion recorded ( Box 21.2 ). The median sulcus may be obliterated when the lobes are hypertrophied or neoplastic. A rubbery or boggy consistency is indicative of benign hypertrophy, whereas stony hard nodularity may indicate carcinoma, prostatic calculi, or chronic fibrosis. A tender fluctuant softness suggests prostatic abscess. Identify the lateral lobes and the median sulcus. The prostatic lobes should feel symmetric. The seminal vesicles are not palpable unless they are inflamed. The Evidence-Based Practice box discusses screening for prostate cancer.
