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Common Anorectal Conditions
A Patient Education Guide

Patient education diagrams illustrating common anorectal conditions.

The diagrams below illustrate three of the most common anorectal conditions. Understanding your condition is an important step toward effective treatment and recovery.

Skin / Tissue
Mucosa / Lining
Sphincter Muscle
Affected Area
Vein / Blood Vessel

1. Hemorrhoids

Hemorrhoids Diagram Dentate line Internal Hemorrhoid External Hemorrhoid Rectum Anus Sphincter

What Are Hemorrhoids?

Hemorrhoids are swollen blood vessels in and around the anal canal. They are one of the most common anorectal conditions.

  • Internal hemorrhoids develop above the dentate line, inside the rectum. They are usually painless but may cause bleeding.
  • External hemorrhoids form below the dentate line, under the skin around the anus. They can be painful, especially if a blood clot forms (thrombosed hemorrhoid).

Common Symptoms

  • Bright red blood on toilet paper or in the bowl
  • Itching or irritation around the anus
  • Swelling, pain, or a lump near the anus
  • Discomfort during bowel movements

2. Anal Fissure

Anal Fissure Diagram Int. Sphincter Ext. Sphincter Muscle spasm Fissure (tear in lining) Rectum Anus

What Is an Anal Fissure?

An anal fissure is a small tear or crack in the thin, moist tissue (mucosa) that lines the anal canal. It often occurs when passing hard or large stools.

  • The tear exposes the underlying muscle, causing it to spasm, which reduces blood flow and makes healing difficult.
  • Most fissures occur along the posterior midline (back wall) of the anal canal.
  • Fissures can be acute (recent, heals within weeks) or chronic (lasting more than 6-8 weeks).

Common Symptoms

  • Sharp, burning pain during and after bowel movements
  • Bright red blood on toilet paper or stool surface
  • A visible crack or tear in the skin around the anus
  • Itching or irritation around the anal area

3. Anal Fistula

Anal Fistula Diagram Abscess Internal Opening (inside anal canal) Fistula Tract (tunnel) External Opening (draining on skin) Rectum Anus Sphincter

What Is an Anal Fistula?

An anal fistula is an abnormal tunnel that forms between the inside of the anal canal and the skin near the anus. It usually develops after an anal abscess that has drained or burst.

  • The internal opening is inside the anal canal, often at the site of an infected gland.
  • The fistula tract is the tunnel that passes through tissue, sometimes crossing through the sphincter muscles.
  • The external opening appears as a small hole on the skin near the anus, which may drain pus or fluid.

Common Symptoms

  • Persistent drainage of pus or fluid near the anus
  • Pain and swelling around the anal area
  • Irritation of the skin around the external opening
  • Recurrent anal abscesses
  • Fever or general discomfort during flare-ups

When Should You See a Doctor?

Many anorectal conditions can be treated effectively, especially when caught early. Please schedule an appointment if you experience:

  • Persistent rectal bleeding or blood in your stool
  • Pain that does not improve with home care within a few days
  • A lump or swelling near the anus that is growing or very painful
  • Drainage of pus or foul-smelling fluid from near the anus
  • Changes in bowel habits lasting more than two weeks

Note: These diagrams are for educational purposes only and are simplified illustrations. Every patient's anatomy and condition is unique. Dr. Henson will discuss your specific diagnosis, anatomy, and treatment options with you during your appointment.