PurposeWhiplash injury can cause internal derangement of the temporomandibular joint (TMJ) and lead to temporomandibular disorders (TMDs). Our aim was to evaluate whether the initial clinical findings in TMD patients with whiplash injury are correlated with their magnetic resonance imaging (MRI) characteristics.Materials and methodsThis case–control study involved 219 patients (135 women, 84 men; mean age: 37.84 years) who visited our orofacial pain clinic with TMD; TMD was diagnosed using the diagnostic criteria for TMD Axis I. Patients were categorized into three groups based on the presence and type of macrotrauma: in the “wTMD” group, patients had suffered whiplash injury; patients in the “pTMD” group had post-traumatic TMD; the “iTMD” group comprised patients who had presented with TMD symptoms and had sustained no macrotrauma. We investigated the presence of disk displacement, effusion, disk deformity, and condylar degeneration, and changes in the lateral pterygoid muscle (LPM). To evaluate the severity of TMD pain and objectively analyze symptoms, we used a visual analog scale (VAS), palpation index (PI), neck PI, dysfunction index, and craniomandibular index (CMI).ResultsThe VAS scores, and the severity indexes of the TMD including PI, neck PI, and CMI were highest in the wTMD patients. Atrophy of the LPM was most commonly seen in the wTMD group, as was disk deformity. In wTMD patients only, VAS score was significantly correlated with stress; it was correlated with headache in wTMD and iTMD patients. The clinical symptoms of TMD were not correlated with MRI findings in the wTMD group. However, alterations in the LPM were strongly correlated with disk displacement.ConclusionIf clinicians recognize alterations in the LPM and disk displacement in the TMJ, they will better understand the clinical symptoms and pathophysiology of TMD with whiplash injury. Whiplash injury may lead to TMD via different mechanisms from other macrotraumas.