Summary
Open-mout h locking due to lateral impingement of the mandibular coronoid process,
lateral to the zygomatic arch, is described in five dogs and one cat. In order to
elucidate the underlying cause of this abnormality, radiographs of temporomandibular
joints of forty dogs, as well as the case history of a human patient, are compared.
Three possible aetiologies are given, namely, flattening of the zygomatic arch, aberrant
architecture of the condylar aspects, or contracture of the pterygoid muscle. An effective
surgical treatment to prevent recur-rence of coronoid impingement was achieved by
ostectomy of the locking part of the coronoid process.
Unilateral protrusion of the mandible is described as a veterinary and comparative
abnormality in five dogs, a cat and a woman. For the impingement of the coronoid process
lateral of the zygomatic arch causing open-mouth locking in the animals, three aetiologies
and an effective ostectomy of the coronoid process are given.
Keywords
Mandibular dislocation - dog - cat - comparative
