A Complementary Radiographic Projection of the Equine Temporomandibular Joint

Abstract

The complexity of the equine skull makes the temporomandibular joint a difficult area to evaluate radiographically. The goal of this study was to determine the optimal angle for a complementary radiographic projection of the equine temporomandibular joint based on a computed tomography (CT) cadaver study. CT was performed on six equine cadaver heads of horses that were euthanized for other reasons than temporomandibular joint disease. After the CT examination, 3D reconstruction of the equine skull was performed to subjectively determine the angle for a complementary radiographic projection of the temporomandibular joint. The angle was measured on the left and right temporomandibular joint of each head. Based on the measurements obtained from the CT images, a radiographic projection of the temporomandibular joint in a rostra-145 degrees ventral-caudodorsal oblique (R45 degrees V-CdDO) direction was developed by placing the X-ray unit 30 degrees laterally, maintaining at the same time the R45 degrees V-CdDO angle (R45 degrees V30 degrees L-CdDLO). This radiographic projection was applied to all cadaver heads and on six live horses. In three of the live horses abnormal findings associated with the temporomandibular joint were detected. We conclude that this new radiographic projection of the temporomandibular joint provides superior visualization of the temporomandibular joint space and the articular surface of the mandibular condyle.

Does temporomandibular joint pathology affect performance in an equine athlete?

“…Radiographic evaluation of the TMJ is possible, but due to the superimposition of adjacent osseous structures, the best diagnostic images are obtained with technically challenging oblique and tangential projections (Ebling et al . ; Townsend et al . ).…”

Functional anatomy of the equine temporomandibular joint: Collagen fiber texture of the articular surfaces

“…Concomitantly, several studies have been performed to evaluate the suitability and potential relevance of advanced imaging techniques, i.e. radiography (Ebling et al, 2009), computed tomography (Rodríguez et al, 2008;Carmalt et al, 2016), ultrasonography (Rodríguez et al, 2007), magnetic resonance imaging (Rodríguez et al, 2010) and TMJ-arthroscopy (May et al, 2001;Weller et al, 2002). Besides these diagnostic and gross anatomical investigations, functional examinations of the equine masticatory movements have been performed.…”

Acquisition and interpretation of radiographs of the equine skull

“… (a) Oblique view of the right temporomandibular joint as described by E bling et al . (). This radiograph demonstrates severe subchondral bone lysis of the mandibular condyle (arrow) that was not evident on the lateral projections.…”