Temporomandibular joint anatomy: Ultrasonographic appearances and sexual dimorphism

Abstract

Introduction Temporomandibular joint (TMJ) dysfunction is common, with a greater prevalence in females. While magnetic resonance imaging (MRI) is commonly used for clinical investigation, ultrasonography represents a potential alternative in some clinical scenarios. We designed a protocol for ultrasonographic evaluation of the TMJ and assessed its reliability. Presentation was compared between the sexes to establish whether an anatomical dichotomy underlies the female preponderance of TMJ dysfunction. Materials and methods Ultrasound imaging of the TMJ was carried out in the longitudinal and oblique planes. Standard images were produced using model skulls and healthy volunteers. Measurements were made between the temporal bone, mandibular condyle, joint capsule and overlying skin, as well as of condylar translation during mouth opening. Both joints were scanned in 50 healthy volunteers. Measurements were repeated to evaluate reliability. A novel classification system was used to assess lateral condylar morphology. Results The protocol facilitated reliable visualization of key anatomical features of the TMJ (average intraclass correlation coefficient = 0.75, truep¯ = 5.4E‐03). Distribution of condylar morphology differed between the sexes. The capsular‐cutaneous distance (‘joint depth’) and condylar‐temporal bone distance (‘interarticular distance’) were significantly greater in males than in females. Conclusions Ultrasonography provides reliable views of the TMJ in two planes: longitudinal and oblique. Observed sexual dimorphism in TMJ anatomy might be associated with the female preponderance of dysfunction. With a standardized scanning protocol, ultrasound could provide a rapid, cost‐effective alternative to MRI as a point‐of‐care imaging tool in TMJ clinics.

Exploring the effect of disc displacement on the risk and severity of condylar erosion in adult temporomandibular disorder patients: A CBCT and MRI study

“…Several factors may contribute to this discrepancy, including variations in hormone levels, 28–30 such as the influence of oestrogen on the development, healing and metabolism of TMJ 46,47 . Anatomical differences impacting joint biomechanics also play a crucial role 48,49 . For instance, male individuals exhibit distinct anatomical characteristics in their craniofacial structure, including longer, wider, and thicker maxillary bones, a more obtuse mandibular angle and a larger condylar head.…”

Diagnostic efficacy of quantitative ultrasonography for anterior disc displacement of the temporomandibular joint

“…Previous studies had indicated that HR-US with a frequency higher than 12 MHz could differentiate the tissues in more detail and therefore achieve better diagnostic performance ( 20 , 21 ). The transducer was normally placed anterior to the tragus and oriented horizontally or longitudinally ( 7 , 8 , 13 ). The horizontal scan can image the transversal slices of the anterosuperior articular compartment, and therefore is commonly adopted to evaluate the disc position relative to the condyle and articular eminence.…”

“…The objective methods based on the measurement of representative anatomical landmarks were proposed to detect intra-articular abnormalities indirectly ( 29 ). The measurement methods were applied to obtain the reference values of normal joints ( 13 , 30 ), as well as to evaluate their association with joint effusion ( 31 - 34 ), joint pain ( 35 ), juvenile idiopathic arthritis (JIA) ( 36 , 37 ), and DD ( 29 , 38 ). The lateral capsular width was the most frequently used variable to investigate structural abnormalities in these studies.…”

“…They were instructed to keep their mouths closed and maintain maximum intercuspal position. The longitudinal scan of the lateral TMJ was conducted as described by Thirunavukarasu et al ( 13 ). In detail, the probe was placed against the patient’s skin on the anatomical position of the TMJ, perpendicular to the zygomatic arch and parallel to the mandible ramus ( Figure 1 ).…”

Oval Type of Human Mandibular Condyle in Panoramic Radiographs of a Tertiary Care Centre: A Descriptive Cross-sectional Study

“… 3 , 5 , 8 - 12 However, very few studies have inspected the shape of the mandibular condyle with potential implications in clinical diagnosis and therapeutic planning. Although Computed Tomography (CT) scan and ultrasonography techniques are utilized for studying mandibular condyle morphology, 11 , 13 , 14 panoramic radiography is one of the most often utilized low-cost methods. 4 , 6 , 15 …”