Evaluation of the lateral pterygoid muscle using magnetic resonance imaging.
OBJECTIVE
The aims of this study were to evaluate the visibility of the lateral pterygoid muscle (LPM) in temporomandibular joint (TMJ) images obtained by MRI, using different projections and to compare image findings with clinical symptoms of patients with and without temporomandibular disorders (TMD).


METHODS
In this study, LPM images of 50 participants with and without TMDs were investigated by MRI. The images of the LPM in different projections of 100 TMJs from 35 participants (70 TMJs) with and 15 participants (30 TMJs) without clinical signs and symptoms of TMD were visible and analysed.


RESULTS
The oblique sagittal and axial images of the TMJ clearly showed the LPM. Hypertrophy (1.45%), atrophy (2.85%) and contracture (2.85%) were the abnormalities found in the LPM. TMD signs, such as hypermobility (11.4%), hypomobility (12.9%) and disc displacement (20.0%), could be seen in TMJ images. Related clinical symptoms, such as pain (71.4%), articular sounds (30.4%), bruxism (25.7%) and headache (22.9%), were observed.


CONCLUSIONS
Patients with TMD can present with alterations in the LPM thickness. Patients without TMD also showed alterations, such as atrophy and contracture, in TMJ images. Recognition of alterations in the LPM will improve our understanding of clinical symptoms and pathophysiology of TMD, and may lead to a more specific diagnosis of these disorders.
Rua Prof Filadelfo Azevedo, 617, apt. 61, 04508-011, São Paulo, SP, Brazil. silvia.dippolito@uol.com.br
S M
SM
D'Ippolito
A M
AM
Borri Wolosker
G
G
D'Ippolito
B
B
Herbert de Souza
M
M
Fenyo-Pereira
D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003286:Contracture / Q000473:pathology; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000473:pathology; D007593:Joint Instability / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009133:Muscular Atrophy / Q000473:pathology; D011446:Prospective Studies; D011626:Pterygoid Muscles / Q000473:pathology*; D016059:Range of Motion, Articular; D013704:Temporomandibular Joint / Q000473:pathology; D013706:Temporomandibular Joint Dysfunction Syndrome / Q000473:pathology*