Rhinoscopy in the dog 1. Anatomy and techniques

DOGS with chronic unilateral or bilateral nasal discharge are seen regularly by clinicians. While imaging techniques such as radiography, computed tomography (CT) and magnetic resonance imaging (MRI) may be used with success in these patients, the changes seen in early cases make radiographic diagnosis difficult, and CT and MRI scans are expensive. Also, these techniques tend to delineate the extent of the changes, whereas diagnosis usually requires tissues for culture, cytology and histology. Rhinoscopy is a useful technique in these patients: it allows the clinician to examine the nasal cavity directly and obtain diagnostic samples of tissue, and it can also be used to assess the progress of treatment. This is the first of two articles on rhinoscopy in the dog. It begins with a refresher on the anatomy of the nose, goes on to describe how to perform rhinoscopy and collect biopsy samples, and illustrates the normal endoscopic appearance of the nasal passages of the dog. An article in the next issue will review, and illustrate the typical endoscopic appearance of, common conditions associated with chronic nasal discharge in dogs.