Definition

Anatomy of the Anus

Choose a preferred language

The anus is the last part of the digestive tract. It's at the end of the rectum. It's where stool comes out of the body. It consists of a muscular ring (called a sphincter) that opens during a bowel movement to allow stool (feces) to pass through and flat cells that line the inside of the anus. Most anal cancers start in these flat lining cells. These are also called squamous cells. The lower part of the anus, where it meets the skin, is called the anal margin.

Cross section of end of digestive system, showing rectum, anus, sphincter, and anal margin.

© 2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.
schedule icon

Schedule an Appointment

Find the right provider and schedule anytime.

View Providers
Related Articles
Read article
Digestive Health
After Hernia Surgery

To speed healing after hernia surgery, take an active role in your recovery. These tips can help.

Read article
Digestive Health
Discharge Instructions: Flushing Your Feeding Tube

You were shown how to flush and care for your tube in the hospital. This sheet helps you remember the steps when you are at home.

Read article
Digestive Health
Discharge Instructions: Ostomy Reversal

Learn how to care for yourself at home after an ostomy reversal.

Read article
Digestive Health
Clear Liquid Diet

You may be put on a clear liquid diet if you are recovering from irritation or infection of the stomach or intestinal tract. This diet may also be used before surgery or special procedures such as a colonoscopy.