Three-dimensional lateral pterygoid muscle volume: MRI analyses with insertion patterns correlation.
We evaluated lateral pterygoid muscle volume in closed and open mouth positions in association with anterior disc displacement, effusion and abnormal articular disc shape from three-dimensional reformations of MRI. A total of 24 MRI of a sample (15 females, 9 males) aged 19-64 years (37.2 years±11.4) were assessed. Segmentation and volumetric assessment of the total, upper and lower heads of the lateral pterygoid muscle were performed using free software. The upper head of the lateral pterygoid muscle had a smaller volume than the lower head at both sides, in the closed- and open-mouth positions. In the open-mouth position, individuals with a subdivided upper head, where one component was inserted in the articular disc and another in the mandibular head, displayed a significantly larger volume of the upper head compared to individuals who had a single attachment to the articular disc (p=0.0130). The lateral pterygoid muscle has different volumes in the closed- and open-mouth positions. Gender affected muscle volume, specifically the upper head component. Insertion type in the upper head also seemed to affect muscle volume.
Department of Orthodontics, University of São Paulo City, São Paulo, São Paulo, Brazil.
Gabriela Sobral de Figueiredo
GSF
Melke
Department of Orthodontics, University of São Paulo City, São Paulo, São Paulo, Brazil. Electronic address: alfcosta@gmail.com.
André Luiz Ferreira
ALF
Costa
Department of Diagnosis and Surgery, São José dos Campos Dental School, São Paulo State University, São José dos Campos, São Paulo, Brazil.
Sérgio Lúcio Pereira de Castro
SLPC
Lopes
Department of Orthodontics, University of São Paulo City, São Paulo, São Paulo, Brazil.
Acacio
A
Fuziy
Department of Radiology, Universidade Paulista, Campinas, SP, Brazil.
Rívea Inês
RI
Ferreira-Santos
D000328:Adult; D000375:Aging / Q000473:pathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008334:Mandible / Q000033:anatomy & histology*; D008875:Middle Aged; D009929:Organ Size; D011626:Pterygoid Muscles / Q000033:anatomy & histology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012737:Sex Factors; D013704:Temporomandibular Joint / Q000033:anatomy & histology*; D013710:Tendons / Q000033:anatomy & histology*; D055815:Young Adult
MRI, Diagnostic imaging; Muscle, Skeletal; Temporomandibular joint