不同功能位颞下颌关节盘MRI对比研究

目的了解颞下颌关节盘在关节运动中的动态变化,为临床影像诊断提供形态依据.方法筛选11具牙列整齐、磨牙完整的新鲜中青年尸头及2例健康青年志愿者,分别行大张口位、下颌前移位、侧移位及闭口位MR扫描.采用Plastination技术将闭口位标本制成横断、斜矢状及斜冠状位三个方位的连续薄层断面标本,比较不同功能位关节盘的断层影像表现.结果大张口位、下颌前移位及下颌侧移位的平衡侧关节盘不同程度地向前移位,关节盘后带变为凹盘或三角状以适应关节结节的形态;下颌侧移位的工作侧关节盘移位不明显.结论颞下颌关节不同功能位时关节盘与髁突、关节窝的关系表现不同.关节盘后带形态变化较大,但关节盘双凹形特征基本保持不变.

Comparative study of the articular disc of temporomandibular joint at different functional positions by MRI

Objective To better understand the dynamic changes of articular disc of the human temporomandibular joint (TMJ) in the mandibular movement so as to provide anatomical data of TMJ for clinical imaging diagnosis. Methods MRI scanning was performed on TMJ articular discs of specimens from 11 fresh cadaver heads with regular dentia lines and complete molar, and from 2 young volunteers without temporomandibular disorders or bruxism at different functional positions of TMJ: wide open mouth, anterior displacement, lateral displacement, and closed mouth positions. Serial thin layer sections of the closed mouth specimens on the transverse, coronal, and sagittal planes were prepared by plastination technique. The sectional imaging manifestations of the articular disc at different functional positions were compared. Results At positions of wide open mouth, forward mandibular displacement, and anterior displacement of the disc at the balancing side of mandibular lateral displacement, the articular disc adapted itself to the articulating surfaces of the bones by turning its posterior zone into concave or triangle shapes. At the working side of mandibular lateral displacement, displacement of articular disc displace was not obvious. Conclusion At different functional positions of TMJ, the relationship of the articular disc with mandibular condyle and the mandibular fossa is different. At each different functional position of mandibles, the discs show a characteristic of biconcave shape.