Mandibular Coronoid Process Displacement: Signs, Causes, Treatment

H. A. W. Hazewinkel; R. Koole; G. Voorhout

doi:10.1055/s-0038-1633143

Veterinary and Comparative Orthopaedics and Traumatology, Table of Contents

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

Authors

H. A. W. Hazewinkel

¹Department of Clinical Sciences of Companion Animals, Section of Small Animal Orthopaedic Medicine and Surgery, Netherlands
R. Koole

²Department of Oro-maxillo-facial Surgery, University Hospital, Netherlands
G. Voorhout

³Department of Veterinary Radiology, University of Utrecht, The Netherlands

Abstract

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

Full Text

References

REFERENCES
1 Thomas RE. Temporomandibular joint dysplasia and open-mouth jaw locking in a Basset Hound: a case report. J Small Anim Pract 1979; 20: 697-701.
2 Robins G, Grandage J. Temporomandibular joint dysplasia and open mouth jaw locking in the dog. J Am Vet Med Assoc 1977; 171: 1072-6.
3 Steward WC, Baker AJ, Lee R. Temporomandibular subluxation in the dog: a case report. J Small Anim Pract 1975; 16: 345-9.
4 Johnson KA. Temporomandibular joint dysplasia in an Irish Setter. J Small Anim Pract 1979; 20: 209-18.
5 Lantz GC, Cantwell HD. Intermittent open-mouth lower jaw locking in five dogs. J Am Vet Med Assoc 1986; 188: 1403-5.
6 Lantz GC. Intermittent open mouth locking of the temporomandibular joint in a cat. J Am Vet Assoc 1987; 190: 1574.
7 Oakcs MG, Lewis DD, Pechman RD. Intermittent open mouth locking in a pcrsian cat. VCOT 1990; 3: 97-9.
8 Koole R, Koole P. Mandibular dysfunction in a case of conversion hysteria. J Craniomand Pract (submitted).
9 Voorhout G. Radiography of the skull in dogs, part 1. Tijdschrift voor Diergcneeskunde 1982; 107: 847-55.
10 Scapino RP. The third joint of the canine jaw. J Morph 1965; 116: 23-50.
11 Koole P, Beenhakker F, dc Jongh HJ, Boering G. A standardized technique for the placement of electrodes in the two heads of the lateral pterygoid muscle. J Craniomand Pract 1990; 8: 154-63.
12 Rowe RF, Caldwell JB. Correction of permanent temporomandibular joint dislocation. J Oral Surg 1970; 28: 222-8.
13 Shira RB, Lister RL. Limited mandibular movement due to enlargement of coronoid process. J Oral Surg 1958; 183-9.
14 Culvenor JA. What is your diagnosis?. J Am Vet Med Assoc 1978; 172: 719-20.
15 Koole P, Dantuma R, Koole R, dc Jongh HJ. Electromyographic findings in a case of hysterical trismus. J Craniomand Pract (submitted).
16 Bradley OC, Arahama T. Topographic Anatomy of the Dog. London: Oliver and Boyd; 1959
17 Dyce KM, Sact WO, Wensing CJG. Text-book of Veterinary Anatomy. Philadelphia: Saunders; 1987
18 Scott JH, Symons NBB. Introduction to Dental Anatomy. London: Livingstone; 1971
19 Burke RH, McNamara JA. Electromyography after lateral pterygoid myotomy in monkeys. J Oral Surg 1979; 37: 630-6.
20 Koch T. Lehrbuch der Veterinar-Anatomie. Jena: Fischer; 1970
21 Tomlinson J, Presnell KR. Mandibular condylectomy: effects in normal dogs. Vet Surg 1983; 12: 148-54.
22 Lantz AC, Cantwell HD, van Vleet JF, Cechner PE. Unilateral mandibular condylectomy: experimental and clinical results. J Am Vet Med Assoc 1982; 18: 883-90.
23 Bennett D, Prymak C. Excision arthroplasty as a treatment for temporomandibular dysplasia. J Small Anim Pract 1986; 27: 361-70.
24 Averill DR. Disease of the muscle. Vet Clin North Am 1980; 10: 223-34.
25 Von Arx DP. Longstanding trismus as the initial presentation of acute catatonic schizophrenia. Br J Oral Maxillofac Surg 1989; 27: 22-6.
26 Shelton GD. Differential diagnosis of muscle diseases in companion animals. Progress Vet Neurol 1991; 2: 27-33.