The rectal exam is an oft-overlooked part of the physical exam. For those practitioners who understand how to interpret it, a lot of information can is obtainable from this simple exam. Anecdotally, we have all heard during our training from experienced physicians about the utility of the rectal exam, and how it should be a part of the physical exam on every patient. And while it is true that in the era of the focused physical exam the rectal exam is no longer performed on every patient, it still has many utilities and is definitely underutilized. It is a valuable diagnostic process in cases including, but not limited to, gastrointestinal bleeding, inflammatory bowel disease, hemorrhoids, constipation, trauma, and neurological disorders.
The rectum is the terminal segment of the large bowel. It is approximately 12 cm long and runs along the concavity of the sacrum. 
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. 
The examiner should explain the reasons for the procedure and obtain verbal consent. Reasons to perform the procedure include:
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 which allows examination.
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. If a prostate infection is suspected, the examination is offered deferred as it may lead to bacterial seeding of the bloodstream. 
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 an urge to defecate.
Rectal examination findings include:
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 an interprofessional Taskforce. 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.
|||Joguet E,Robert R,Labat JJ,Riant T,Guérineau M,Hamel O,Louppe JM, Anatomical basis of digital rectal examination. Surgical and radiologic anatomy : SRA. 2012 Jan; [PubMed PMID: 21643789]|
|||Steggall MJ, Digital rectal examination. Nursing standard (Royal College of Nursing (Great Britain) : 1987). 2008 Jul 30-Aug 5; [PubMed PMID: 18777822]|
|||Dionne JC,Johnstone J,Smith O,Rose L,Oczkowski S,Arabi Y,Duan EH,Lauzier F,Alhazzani W,Alam N,Zytaruk N,Campisi J,Cook DJ, Content analysis of bowel protocols for the management of constipation in adult critically ill patients. Journal of critical care. 2020 Aug; [PubMed PMID: 32408108]|
|||Rex DK,Boland CR,Dominitz JA,Giardiello FM,Johnson DA,Kaltenbach T,Levin TR,Lieberman D,Robertson DJ, Colorectal Cancer Screening: Recommendations for Physicians and Patients From the U.S. Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2017 Jul [PubMed PMID: 28600072]|