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Anal fissure
Make it clearer
An anal fissure is a lengthwise tear in the anoderm, the very thin skin that lines the inside of the anal canal, just below a border called the dentate line.
Most fissures start with local trauma: the passage of hard or bulky stool, irritation that keeps coming back, surgery in the area. That tissue is delicate and breaks under repeated friction or pressure from inside.
What explains the rest is what happens next. Around the canal there is a ring of muscle, the internal anal sphincter, which in people with a fissure tends to stay too tight, squeezing more than it should. As it squeezes, it chokes off circulation in the area, and with less blood the wound gets less of what it needs to heal; that lack of blood supply is called ischemia. The wound hurts, the pain tightens the muscle further, and the muscle keeps the wound from closing. It is a crack at the corner of the mouth that reopens every time you open your mouth.
In brief
An anal fissure is a lengthwise tear in the anoderm, the lining of the anal canal, below the dentate line.
Most fissures begin with local trauma, such as the passage of hard stool, in tissue that is highly sensitive to repeated friction and pressure.
The fissure is usually accompanied by increased tone in the internal anal sphincter, which reduces local blood flow, causes ischemia and delays healing.
It is a crack at the corner of the mouth that reopens every time you open your mouth.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingAnal Fissures, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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