Vet Comp Orthop Traumatol 1993; 06(01): 29-35
DOI: 10.1055/s-0038-1633143
Clinical Report
Schattauer GmbH

Mandibular Coronoid Process Displacement: Signs, Causes, Treatment

H. A. W. Hazewinkel
1  Department of Clinical Sciences of Companion Animals, Section of Small Animal Orthopaedic Medicine and Surgery, Netherlands
R. Koole
2  Department of Oro-maxillo-facial Surgery, University Hospital, Netherlands
G. Voorhout
3  Department of Veterinary Radiology, University of Utrecht, The Netherlands
› Author Affiliations
Further Information

Publication History

Received for publication: 21 October 1992

Publication Date:
06 February 2018 (online)


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.