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Anal Health

Overview, Anal Anatomy, STDs, Anal Health, Anal Cancer

Physician-developed and -monitored.

Original Date of Publication: 01 Aug 2001
Reviewed by: Stanley J. Swierzewski, III, M.D.

Original Source:

Home » Anal Health » Overview, Anal Anatomy, STDs, Anal Health, Anal Cancer

The anus (opening of the anal canal) functions as eliminator of waste, sexual organ, and intake orifice for treatment (e.g., suppository, enema). It is necessary to care for the anus, anal canal, and rectum if they are involved in sexual activity.

Sexually transmitted diseases (STDs) can be transmitted through anal sex and can affect the anus itself. And anal cancer is associated with STDs in men and women. Damage to the internal and external skin and tissue of the anus jeopardizes health, causes pain, and impairs function.

Recently, infection with a strain of potentially deadly bacteria (called methicillin-resistant Staphylococcus aureus or MRSA) has been reported in men who have sex with men (MSM). These bacteria can cause life-threatening infections that are resistant to antibiotic treatment. Some forms of MRSA live in the anal area and can be passed between sexual partners.

Anal Anatomy
Basic anal anatomy includes the following:

  • Anus
  • Anal canal
  • Rectum

The anus is an orifice, the opening of the anal canal. Just behind it, in the anal canal, lie an exterior sphincter and an interior sphincter. A sphincter is a circular muscle that constricts and expands. Anal sphincters constrict to retain feces and expand to allow it and flatus (gas) to pass during defecation. The anal canal is the first 2 inches of skin after the anus; it is closed while at rest and open during defecation and penetration. It leads to the rectum, the cavity that runs vertically from the end of the colon to the anal canal. The rectum is approximately 5 inches long and 1 1/2 inches wide. It stores feces prior to defecation.

The Anus as a Sexual Organ
The abundance of nerve endings in the anal region and rectum makes anal sex pleasurable for many women and men. Some men get pleasure from anal penetration that stimulates the prostate gland, which lies between the rectum and the rest of the male reproductive organs.

Anal sexual behaviors include the following:

  • Anal stimulation and insertion using the fingers
  • Anal stimulation using sex toys (e.g., vibrators, dildos, etc.)
  • Oral-to-anal sex, or "rimming"
  • Penis-to-anus penetration
  • Pleasurable use of enema (introduction of fluid into the rectum)

Maintaining anal health is important for men and women who enjoy any type of anal sex. Anal health is probably of greatest importance to gay men who practice penis to anus penetration regularly.

Sexually Transmitted Diseases
Infected people may spread sexually transmitted diseases (STDs) through anal sex when blood, semen, or fluid is shared. Hepatitis (inflammation of the liver) and HIV (human immunodeficiency virus) are two serious STDs whose symptoms do not appear on the anus. STDs that affect the anus include:

  • Herpes simplex virus (HSV); infection of the skin and genital mucosa (mucous membrane); causes recurring sores and pain)
  • Gonorrhea (inflammation of genital mucosa; infectious discharge; can affect primarily the skin and joints, but later can involve the central nervous system and heart valves)
  • Human papillomavirus (HPV; causes genital and anal warts; may cause cervical, anal, and penile cancers)
  • Parasites (affect the entire gastrointestinal tract)
  • Syphilis (bacterial infection causing lesions in any tissue; often affects the nervous system and heart)

It is possible to acquire an STD without penetration. Oral-to-anal contact, whether from kissing or from oral contact with fingers that have been touching the anus can spread bacteria and cause infection. Even the use of sex toys may transmit certain diseases. Practicing safer sex can prevent STDs in men and women.

Anal Fissure
An anal fissure is a small tear in the skin and tissue of the anus. It can bleed, itch, and become extremely sore, making bowel movement, sitting, and sex painful. Anal sex without lubrication, a hard bowel movement, and inflammation of anal tissue can cause a fissure. Some heal within a couple of weeks, especially if therapeutic cream, warm baths, and stool softeners are used. Others require surgical removal of the tear, which is exacerbated by sphincter movement, and the underlying scar tissue. People with fissures are advised to avoid anal sex. The bleeding that occurs with a tear increases the risk for STDs.

Hemorrhoids are lumps that may appear outside the anus or inside the anal canal. They are inflamed enlarged veins that rarely require surgery. Hemorrhoids may be painful or itchy and may also bleed. Risk factors for hemorrhoids include strenuous or frequent bowel movements. Anal sex does not cause hemorrhoids but may exacerbate them. Eating a high fiber diet, taking lukewarm baths (Sitz bath), and using witch hazel to wipe after bowel movements may help.

Anal Health
Lubrication, cleanliness, and condoms reduce the chance of tearing and minimize the risk of transmitting disease during anal sex. The anus does not produce lubrication; it must be applied. Anal skin and tissue is likely to tear when it is dry, so lubrication is important before penetration. Lubricant should be water based or "condom or latex friendly," not oil based. Oil based lubricants destroy latex condoms.

Washing the anal region before and after anal sex reduces the amount of bacteria that could be spread from partner to partner, but may also remove some of the natural protection the body has to infection. Condoms can help prevent the spread of STDs when worn prior to any contact. Oral-to-anal contact is safest when using a dental dam, a flat, sheet like condom that provides a barrier between the mouth or fingers and the anus.

Overuse of enemas can destroy the normal, healthy balance of bacteria in the lower intestine.

Lubricants that contain nonoxonyl-9 (N9) spermicide should be avoided. Recent data suggests that N9 may actually increase the risk for transmission of HIV.

Anal Cancer
The risk for anal cancer is a concern for men and women who have anal sex. It can produce malignant tumors inside and outside the anal canal. Many people with early anal cancer have no symptoms. The major risk factor for anal cancer is infection with HPV. Many LGBT practitioners are advising routine anal Pap smears to detect the early changes that might indicate a risk of developing anal cancer. There are no long term studies, but some providers advise that any male with a history of having anal sex should be screened. Also women with cervical dysplasia should be screened. About twice as many HIV-positive men as uninfected men develop anal cancer, so this group is particularly at risk. Although anal cancer accounts for less than 5% of all digestive and intestinal tract cancers, the rate of incidence is rising.

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  1. 21 Jul 2008
    Suggestion: a section on the sphincter muscle, rel...Read

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