Rectal thermometry is taking a person's temperature by inserting a thermometer into the

rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the sigmoid colon) at the l ...

via the

anus The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, ...

. This is generally regarded as the most accurate means of temperature-taking, but some may consider it to be an invasive or humiliating procedure. Thus, it is often used sparingly and primarily on infants, children, or adults for whom taking an oral temperature would risk injury (e.g., an unconscious patient, a post-oral surgery patient, or a person suffering a

seizure An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with lo ...

) or be inaccurate (due to recently ingested liquids or breathing through the mouth).

History

The precise history of rectal thermometry is largely unknown, but

medical thermometer A medical thermometer (also called clinical thermometer) is a device which is used for measuring human or animal body temperature. The tip of the thermometer is inserted into the mouth under the tongue (''oral'' or ''sub-lingual temperature''), ...

s have long been made in a tube shape that fits into the anus. Medical literature shows the practice dating back to at least the 18th century, and it is probable that rectal thermometry was thought to be a safer alternative to oral temperature-taking, due to the use of mercury and other toxic chemicals in early thermometers. In 1966

Time Magazine ''Time'' (stylized in all caps) is an American news magazine based in New York City. For nearly a century, it was published weekly, but starting in March 2020 it transitioned to every other week. It was first published in New York City on Ma ...

noted

Near dawn every morning, a nurse walks into the hospital room, wakes the patient and subjects him to what for many remains a humiliating procedure, although it has become routine: insertion of a rectal thermometer.

As thermometry-related technology improves in the 21st century, rectal thermometry is becoming decreasingly pervasive, but it is still the preferred method for taking the temperature of infants and pets.

Use and procedure

Rectal thermometry is widely used in

veterinary medicine Veterinary medicine is the branch of medicine that deals with the prevention, management, diagnosis, and treatment of disease, disorder, and injury in animals. Along with this, it deals with animal rearing, husbandry, breeding, research on nutri ...

and

pediatrics Pediatrics ( also spelled ''paediatrics'' or ''pædiatrics'') is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, paediatrics covers many of their youth until the ...

, as well as by adults at home who want the most accurate possible temperature reading and overlook the invasive nature associated with the painless procedure. It is accomplished by inserting the tip of a thermometer, usually lubricated with

personal lubricant Personal lubricants (colloquially termed lube) are specialized lubricants used during sexual acts, such as intercourse and masturbation, to reduce friction to or between the penis and vagina, anus or other body parts or applied to sex toys to red ...

to eliminate friction and aid in insertion past the tightly retentive anal

sphincter A sphincter is a circular muscle that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning. Sphincters are found in many animals. There are over 60 types in the h ...

, to a depth of, for an adult , or for a child between . The thermometer tip must then be left in place until a reading can be derived, usually about 3 minutes for mercury thermometers and 1 minute for newer electronic types. It is important to remember that the normal human core temperature range measured with a rectal thermometer spans from 98.6 to 100.4 degrees Fahrenheit (37.0 to 38.0 degrees Celsius). Rectal thermometers are often colored cherry red to differentiate them from oral or axillary thermometers, as well as have a shorter, squat, pear, or stubby bulb shape. They are not meant to be used interchangeably with other types of thermometers.

References

{{DEFAULTSORT:Rectal Thermometry Medical tests Rectum