Atlas of Normal Radiographic Anatomy and Anatomic Variants in the Dog and Cat - E-Book

Donald E. Thrall, Ian D. Robertson

• Publisher: Saunders
• Year: 2015
• eBook ISBN: 9780323312776
• Edition: 2
• Topic: Medicine
• Subtopic: Veterinary Medicine

- NEW! Companion website features additional radiographic CT scans and more than 100 questions with answers and rationales.- NEW! Additional CT and 3D images have been added to each chapter to help clinicians better evaluate the detail of bony structures.- NEW! Breed-specific images of dogs and cats are included throughout the atlas to help clinicians better understand the variances in different breeds.- NEW! Updated material on oblique view radiography provides a better understanding of an alternative approach to radiography, particularly in fracture cases.- NEW! 8.5" x 11" trim size makes the atlas easy to store.

Chapter 1

Basic Imaging Principles and Physeal Closure Time

How to Use This Atlas

As described in the Preface, a radiographic atlas is intended to help decide whether any given radiographic finding is normal or abnormal. Determining normal from abnormal is one of the most difficult parts of interpreting a radiograph (if not the most difficult). No atlas will be able to provide a definitive answer to the “What is that, and is it normal?” question in every circumstance, but the information in this atlas can help guide the decision-making process.

The best way to use this atlas is to spend some time with it, and get to know it. Of course, labeled images are provided—every atlas needs these. But, contrary to a pure picture atlas, some of the most valuable information in this atlas is contained in the text. Being familiar with the text, which is brief and focused, and noting the important principles that have been augmented with illustrative examples can help formulate a basis for interpretation that extends beyond structure identification alone.

What Is Normal?

Many dogs and cats have congenital or developmental changes that are apparent radiographically but insignificant clinically. Discussing some of these common variations in this atlas, along with normal structures, is justified even though they are not completely normal because they are often confused with disease. This book demonstrates much of the morphologic diversity currently present in domestic canine and feline companions that has come to be commonly accepted as normal or clinically insignificant.

Why Are Computed Tomography Images Included in This Atlas?

Because this is a radiographic atlas, the majority of images are radiographs. This book is not intended to be an atlas of normal computed tomography (CT) appearances, but some CT images are included to reinforce the appearance of selected structures in radiographs. A radiograph is a 2-dimensional image of a 3-dimensional (3-D) object, and, as a result, spatial localization of structures cannot always be done accurately, even with multiple views of the object or patient. CT images are tomographic, creating multiple image slices of the volume of interest. Slicing the patient solves the problem of spatial localization and can assist with understanding radiographic anatomy more thoroughly. Additionally, CT images, which are typically acquired in a transverse plane, can be reformatted into other planes, typically sagittal and dorsal planes, for clarification or to improve structure visualization. Transverse CT images can even be reformatted into volumetric images for illustration of complex structures. Therefore, a careful selection of planar and volumetric CT images has been included with this goal in mind.

Radiographic Terminology

This book uses the standard method for naming radiographic projections approved by the American College of Veterinary Radiology.¹ In general, this naming method is based on anatomic directional terms (as defined by the Nomina Anatomica Veterinaria) combined with the point-of-entrance to point-of-exit of the primary x-ray beam. In other words, any radiograph can be named by knowing the point of entrance and point of exit of the primary x-ray beam. For example, a spinal radiograph made with a dog lying in dorsal recumbency would be cal...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Preface
• Acknowledgments
• The Images
• 1 Basic Imaging Principles and Physeal Closure Time
• 2 The Skull
• 3 The Spine
• 4 The Thoracic Limb
• 5 The Pelvic Limb
• 6 The Thorax
• 7 The Abdomen
• Index
• Color Plate