Anatomy, Variants, and Interpretation Paradigm

This chapter reviews normal radiographic anatomy of the thorax, thoracic variants, and “fake-outs,” and presents an interpretation paradigm for the routine evaluation of the thorax. High-quality thoracic radiographs are the end goal for all thoracic imaging studies. Knowledge of thoracic anatomy is power when it comes to interpretation of thoracic radiographs. Normal variations of thoracic structures present the potential for misdiagnosis. There is large variation in the size and shape of the thorax based on the different dog breeds. The variants will be divided into the four compartments that form the basis for the interpretation paradigm of the thorax: extrathoracic structures, pleural space, pulmonary parenchyma, and the mediastinum. The mediastinum can be divided into thirds with the cardiac silhouette being located in the ventral middle mediastinum. The most common variant of the caudal mediastinum is associated with the esophagus.