physics

Rectal examination

Rectal examination is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Rectal examination rather than just read about it. In short: Digital rectal examination (DRE), also known as a prostate exam (Latin: palpatio per anum (PPA), lit. 'palpation through the anus'), is an internal examination of the rectum performed by a healthcare provider. Prior to a 2018 report from the United States Preventive Services Task Force, a digital exam was a common component of annual medical examination for older men, as it was thought to be a reliable screening tes…

Key takeaways

Rectal examination belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Rectal examination to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Rectal examination from memory before moving on to harder problems.

Reference excerpt

Digital rectal examination (DRE), also known as a prostate exam (Latin: palpatio per anum (PPA), lit. 'palpation through the anus'), is an internal examination of the rectum performed by a healthcare provider. Prior to a 2018 report from the United States Preventive Services Task Force, a digital exam was a common component of annual medical examination for older men, as it was thought to be a reliable screening test for prostate cancer.

Usage This examination may be used:

for the diagnosis of prostatic disorders, benign prostatic hyperplasia and the four types of prostatitis. Chronic prostatitis/chronic pelvic pain syndrome, chronic bacterial prostatitis, acute (sudden) bacterial prostatitis, and asymptomatic inflammatory prostatitis. The DRE has a 50% specificity for benign prostatic hyperplasia. Vigorous examination of the prostate in suspected acute prostatitis can lead to seeding of septic emboli and should never be done. Its utility as a screening method for prostate cancer however is not supported by the evidence; for the evaluation of certain clinical symptoms: a male with change in urinary ability, impotence, or dysuria (blood in the urine), pain with bowel movements; a DRE with a FOBT might have value for a person with anemia in the emergency room who has no other identifiable cause for anemia, is not actively bleeding, and there is concern that gastrointestinal malignancy may be the cause for their anemia; a true active gastrointestinal bleed: vomiting blood, vomiting coffee-grind like material, defecating blood or black tarry stools that can not be easily attributed to facial trauma or oral surgery, eating beets or anything with red food dye or overuse of NSAIDS/over the counter pain medication. Doing a rectal exam to examine stool color may provide a clue as to the location of the bleed but is not a reliable indicator; for the diagnosis of appendicitis or other examples of an acute abdomen (i.e. acute abdominal symptoms indicating a serious underlying disease). Although a Journal of Emergency Medicine paper concludes: "We found the DRE to have a limited role in the diagnosis of acute, undifferentiated abdominal pain and acute appendicitis."; for the estimation of the muscle tone of the anal sphincter, which may be useful in case of fecal incontinence or neurologic diseases, including traumatic spinal cord injuries; traditionally, the digital rectal examination (DRE) was considered an essential part of the physical examination for all trauma patients. However, the sensitivity of the DRE for injuries of the spinal cord, pelvis, and bowel is poor, and false positive and negative results are common. Thus, routine performance is unnecessary and generally unhelpful. The examination is warranted in cases where urethral injury or penetrating rectal injury is suspected; in females, for the limited gynecological palpations of internal organs when the vaginal vault cannot be accessed or it is too painful (vaginal atrophy); for examination of the hardness and color of the feces (i.e. in cases of constipation, and fecal impaction); prior to a colonoscopy or proctoscopy; to evaluate hemorrhoids although internal hemorrhoids are often too soft to be felt, a visual inspection may be more useful; in newborns to exclude imperforate anus; through the insertion of medical devices including thermometers or specialized balloons; to identify digestion problems, parasites, organ damage, anal bruising, and foreign objects in the rectal cavity;

Usage as a screening tool

In colorectal cancer screening of asymptomatic adults aged 50 to 75 Even though 1 in 4 colorectal cancers (CRC) is located in the rectum, little evidence supports the effectiveness of using the DRE for rectal cancer detection and it is not recommended in the colorectal cancer screening guidelines. The DRE is inadequate as a screening tool for colorectal cancer because it examines less than 10% of the colorectal mucosa; sigmoidoscopy is preferred. Although the DRE is commonly used as a way to obtain a stool sample for a FOBT (fecal occult blood test) in an office based setting, this is an insufficient way of screening for colorectal cancer and is not recommended. A single office-based FOBT (fecal occult blood test) performed following a digital rectal examination (DRE) is not an adequate screen due to low sensitivity for advanced tumor and colorectal cancer. Screening for colon cancer this way does not meet HEDIS, Medicare or American Cancer Society standards. The FOBT has never been validated for any purpose other than as a take home colon cancer screening test. A paper published in the Journal of General Internal Medicine states, "While FOBT done appropriately (taken home and used according to the instructions) is an important screening option, in-office FOBT may be worse than no screening at all because it misses 95% of cases of advanced tumor, giving many patients a false sense of reassurance."

In prostate cancer screening of asymptomatic men aged 55 to 69 In men aged 55–69 who have been counseled on the known harms and potential benefits of prostate cancer screening, the U.S. Preventive Service Task Force May 2018 statement states, "The use of digital rectal examination as a screening modality is not recommended because there is a lack of evidence on the benefits." The American Academy of Family Physicians states, "Digital Rectal Exam does not improve detection of prostate cancer and should not be performed as a part of screening." The American Urological Association 2013 (reviewed and validity confirmed 2018) guideline panel states, "The literature supporting the efficacy of digital rectal exam (DRE) for screening with the goal of reducing prostate cancer mortality provide limited evidence to draw conclusions." "The guideline panel could find no evidence to support the continued use of DRE as a first-line method of screening." Although DRE has long been used to diagnose prostate cancer, no controlled studies have shown a reduction in the morbidity or mortality of prostate cancer when detected by DRE at any age. A meta-analysis published in the Annals of Family Medicine concluded: "Given the considerable lack of evidence supporting its efficacy, we recommend against routine performance of DRE to screen for prostate cancer in the primary care setting."

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Rectal examination

Start with the simplest possible case. Write down what Rectal examination claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Rectal examination before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Rectal examination ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Rectal examination

In research: Rectal examination appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Rectal examination in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Rectal examination is common in secondary-school and first-year university syllabi. It links to neighbouring topics Diagnostic gastroenterology, Physical examination, Rectum, so understanding it makes those chapters shorter.
In everyday life: Look for Rectal examination outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Rectal examination in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Rectal examination means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Rectal examination out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Rectal examination in simple terms?

Why does Rectal examination matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Rectal examination?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Rectal examination.