Question

What is the approximate length of the anal canal?

• A. 10 - 15 mm
• B. 15 - 20 mm
• C. 25 - 30 mm
• D. 35 - 40 mm

Hint:

The anal canal is about 3.8 cm long.

Answer 1

The Correct Option is D

Step 1: The anal canal is the terminal part of the alimentary canal. It begins at the anorectal junction, which lies about 2 to 3 cm in front of and slightly below the tip of the coccyx.

Step 2: From the anorectal junction the canal passes downward and backward through the pelvic diaphragm to open at the anus, located in the natal cleft about 4 cm below and in front of the coccyx.

Step 3: The classic textbook length of the anal canal is about 3.8 cm, which equals roughly 38 mm. Unlike the colon, it has no sacculations or taeniae.

Step 4: 38 mm falls within the 35 to 40 mm range, so the correct option is 35 to 40 mm. The shorter ranges are too small to match the anatomical length.