开、闭口位颞下颌关节的塑化断层、磁共振形态对比研究

Comparative study of MRI and plastination section of the temporomandibular joint at closed-mouth and wide-open mouth positions

目的 了解颞下颌关节在不同运动位置时的形态改变。方法 选择 7具牙列整齐、磨牙完整的新鲜中青年尸头 ,摆置成牙尖交错咬合闭口位、大张口位 ,MRI扫描后采用生物塑化 (plastination)技术制成横轴位、斜矢状位、斜冠状位的连续薄层断面标本 ,比较开、闭口位关节的形态变化。结果 大张口位时 ,关节盘受盘韧带、翼外肌的影响 ,随髁状突向前下移位 ,其形态适应骨性关节面的形态发生改变 ,盘移动度不及髁状突 ;关节周围血管呈网状分布 ,明显扩张状。

Objective To investigate the morphological changes of the human temporomandibular joint (TMJ) at different positions. Methods Seven fresh cadaver head specimens with regular dentation and complete molars were observed at different positions, including 5 cases of closed mouth position and 2 cases of wide open mouth position. Serial thin sections at the transverse plane, adjusted coronal plane, and sagittal plane were prepared by the plastination technique after magnetic resonance imaging (MRI) scanning. The morphologic changes of human TMJs at the closed mouth and open mouth positions were compared. Results At the position of wide open mouth, the disc of the TMJ moved anteriorinferiorly and changed shapes following processus condylaris under the influence of ligaments and lateral pterygoid muscle. The extent of disc movement was less than that of the processus condylaris. Conclusion The sagittal plane is the best position for the observation of the morphological changes of the TMJ.