The erect chest X-ray is often the first investigation in the evaluation of free intra-peritoneal gas. This article reviews the appearances of free intra-peritoneal gas on both chest and abdominal radiographs.

A widened mediastinum is a common finding on the plain chest radiograph. It is often encountered in the acute setting, where correct interpretation is essential to guide immediate management.

This pictorial review briefly describes the basic principles of computed tomography scanning of the brain. A series of commonly encountered intracranial pathologies is then reviewed.

The plain abdominal radiograph is one of the most frequently requested X-ray examinations by junior surgical and accident and emergency staff. Interpretation is often difficult, but this review outlines normal appearances, suggests a strategy for evaluation, and covers the common pathological appearances seen in hospital practice.