Megarectum is a large
rectum
The rectum (: rectums or recta) is the final straight portion of the large intestine in humans and some other mammals, and the gut in others. Before expulsion through the anus or cloaca, the rectum stores the feces temporarily. The adult ...
as a result of underlying
nerve
A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the Electrochemistry, electrochemical nerv ...
supply abnormalities or
muscle
Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...
dysfunction, which remains after disimpaction of the rectum.
The Principles of Surgery textbook describes any rectum that can hold more than 1500cc of fluid as a megarectum. The term megarectum is also used for a large rectal mass on
rectal examination
Digital rectal examination (DRE), also known as a prostate exam (), 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 c ...
, a wide rectum on an
abdominal x-ray
An abdominal x-ray is an x-ray of the abdomen. It is sometimes abbreviated to AXR, or KUB (for kidneys, ureters, and urinary bladder).
Indications
In adults, abdominal X-rays have a very low specificity and cannot rule out suspected obstructi ...
, the presence of impaired rectal sensation or the finding of large maximal rectal volumes on
anorectal manometry
Anorectal manometry (ARM) is a medical test used to measure pressures in the anus and rectum and to assess their function. The test is performed by inserting a catheter, that contains a probe embedded with pressure sensors, through the anus and in ...
. In addition, can be the bloating of the colon due to infection, also called
megacolon
Megacolon is an abnormal dilation of the colon (anatomy), colon (also called the large intestine). This leads to hypertrophy of the colon. The dilation is often accompanied by a paralysis of the peristalsis, peristaltic movements of the bowel. In ...
.
On
defecography
Defecography (also known as proctography, defecating/defecation proctography, evacuating/evacuation proctography or dynamic rectal examination) is a type of medical radiological imaging in which the mechanics of a patient's defecation are visuali ...
, megarectum is suggested by a rectal width of >9 cm at the level of the distal
sacrum
The sacrum (: sacra or sacrums), in human anatomy, is a triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30.
The sacrum situates at the upper, back part of the pelvic cavity, ...
.
References
* https://academic.oup.com/jscr/article/2020/3/rjaa047/5801062
Further reading
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External links
Gastrointestinal tract disorders
Rectum
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