ABSTRACT
INTRODUCTION The ear of the dog and cat is composed of three parts: the external ear, the middle ear, and the inner ear1-3. Together these components allow the animal to locate a sound and the direction from which it emanates, to orientate the head in relation to gravity, and to measure acceleration and rotation of the head. Selective breeding, of dogs in particular, has resulted in a wide variation in relative size and shape of the components of the external ear. Compare, for example, the French Bulldog, the Cocker Spaniel, the German Shepherd Dog, the St. Bernard, and the Persian cat. The pinnal shape and carriage, the diameter of the external ear canal, the degree of hair and amount of soft tissue within the external ear canal, and the shape of the skull within which the middle and inner ear lie vary from one breed to another. Despite this anatomic variation the essential relationship between the various components of the external, middle, and inner ear is preserved (1).
