Anal atresia

Case contributed by Dr Jeremy Jones


Neonate without passage of meconium.

Patient Data

Age: 2 days
Gender: Male

Marked gaseous distension of the large bowel, particularly of the rectosigmoid. Features here are of a distal large bowel obstruction.


The prone lateral view is performed to demonstrate the position of the most distal portion of the large bowel and therefore determine whether it is a high or low anal atresia.

Case Discussion

Distal large bowel obstruction should trigger a differential diagnoses that includes:

Anal atresia should be obvious clinically and you'd hope that the clinicians tell you on the request card.

One way to assess the level of distal obstruction is to perform a lateral radiograph in the prone position although some centers perform an invertogram. This allows assessment of whether the atresia is high or low depending on whether the most distal portion of the gas-filled bowel is above or below the levator.

PlayAdd to Share

Case information

rID: 30845
Published: 6th Sep 2014
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.