Why TMJ Imaging in Dogs and Cats Is Harder Than You Think – A Practical Radiology Review

Imaging of the Canine and Feline Temporomandibular Joint: A Review

Tobias Schwarz; Renate Weller; Alison M. Dickie; Martin Konar; Martin Sullivan

Background

The temporomandibular joint (TMJ) of dogs and cats presents a diagnostic challenge due to its complex anatomy and deep location within the skull. Although primary TMJ disease is relatively uncommon, many conditions affecting mastication, dental occlusion, trauma, or skull pathology require careful TMJ assessment. The purpose of this review is to summarize normal anatomy, radiographic appearance, and imaging findings of common TMJ disorders in dogs and cats, with emphasis on conventional radiography and computed tomography (CT), and limited discussion of magnetic resonance imaging (MRI).

Methods

This article is a narrative review of existing veterinary literature and institutional experience. The authors describe TMJ anatomy and physiology, standard and oblique radiographic positioning techniques, and CT imaging protocols. Imaging characteristics of a wide range of TMJ disorders are reviewed, including developmental, traumatic, degenerative, infectious, and neoplastic conditions. Illustrative radiographs, CT images, and limited MRI examples are used to demonstrate typical findings.

Results

Dorsoventral radiographs are identified as the most accessible and informative initial view for TMJ evaluation, while oblique projections are necessary to assess the joint without superimposition. CT is shown to provide superior visualization of bony structures, subtle fractures, ankylosis, and neoplasia compared to radiography. Characteristic imaging findings are described for conditions such as craniomandibular osteopathy, TMJ dysplasia, luxation and subluxation, fractures, ankylosis, degenerative joint disease, infection, and tumors. MRI is noted to be useful for evaluating masticatory muscles and myositis, although its role in TMJ imaging in small animals remains limited.

Limitations

The review highlights that radiographic assessment of the TMJ is limited by superimposition and positioning difficulties, particularly in oblique views. Soft tissue structures of the TMJ, including the articular disc and joint capsule, are not well visualized with radiography or CT. MRI use in canine and feline TMJ disorders is sparsely reported, and standardized protocols or diagnostic criteria are lacking. Additionally, some described techniques require validation in larger clinical populations.

Conclusions

Imaging of the TMJ is an essential component of the diagnostic work-up in dogs and cats with mandibular trauma, malocclusion, pain, or restricted jaw motion. While radiography remains the primary screening tool, CT is the imaging modality of choice for detailed evaluation of bony TMJ pathology and treatment planning. MRI shows promise for assessing masticatory muscle disease but its clinical value for TMJ disorders requires further investigation. Accurate imaging, combined with appropriate positioning and modality selection, is critical for correct diagnosis and management of TMJ disease in small animals.

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