If you are interested in improving your knowledge and skill in interpretation of an abdominal X-ray, work through this free online tutorial entitled 'Abdominal x-ray - system and anatomy'. 
There are several other related tutorials in this series, focusing on different aspects of interpretation of abdominal x-rays:

Abnormal bowel gas patterns,  Abnormal calcification,  Abnormal soft tissue & bones.

Access the tutorial Interpreting Abdominal X-rays