Schmitter Marc, Kress Bodo, Ludwig Christina, Koob Andreas, Gabbert Olaf, Rammelsberg Peter
Department of Prosthodontics and Neuroradiology, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
Radiology. 2005 Aug;236(2):559-64. doi: 10.1148/radiol.2361040223.
To assess the normal position of the temporomandibular joint (TMJ) disk relative to the condyle by using coronal magnetic resonance (MR) imaging in asymptomatic volunteers.
This study was approved by the review committee for human research, and all subjects signed an informed consent form. Thirty symptom-free volunteers without histories of TMJ disorders underwent standardized clinical examinations. Afterward, bilateral sagittal oblique and coronal oblique MR images were acquired with the patient's mouth opened and closed. The coronal oblique opened- and closed-mouth images were analyzed by using computer software. The medial and lateral edges of both the TMJ disk and the condyle were marked for these imaging examinations by using the section through the posterior 3 mm of the disk. To eliminate the effect of different magnifications and/or distortions, the distance between these points was measured automatically and divided by the largest mediolateral dimensions of the condyle. To assess the reliability of the measurements, four observers evaluated the position of the disk in the coronal plane. To assess the changes in position of the posterior 3 mm of the disk in the coronal plane in the closed- and opened-mouth positions, the Wilcoxon signed rank test for matched pairs was used. Interobserver measurement reliability was evaluated by using interclass correlation coefficients (ICCs).
Analysis of the coronal closed-mouth disk position revealed a medial position of the TMJ disk relative to the condyle in 11 (21%) of 52 analyzed joints. In the opened-mouth position, the medial location of the disk was more frequent: 29 (85%) of 34 analyzed joints exhibited a medial position of the disk relative to the condyle in this plane. This increasingly medial position of the disk was statistically significant (P < or = .001). Measurement reliability assessment revealed sufficient results (ICC > or = 0.7).
At both closed- and opened-mouth MR imaging, a medially located TMJ disk seems to be within the normal range of variation. The disk seems to shift even more medially when the mouth is opened.
通过对无症状志愿者进行冠状位磁共振成像（MR），评估颞下颌关节（TMJ）盘相对于髁突的正常位置。
本研究经人体研究审查委员会批准，所有受试者均签署了知情同意书。30名无颞下颌关节疾病史的无症状志愿者接受了标准化临床检查。之后，在患者张口和闭口时采集双侧矢状斜位和冠状斜位MR图像。使用计算机软件分析冠状斜位张口和闭口图像。在这些成像检查中，通过穿过盘后3mm的截面，标记颞下颌关节盘和髁突的内侧和外侧边缘。为消除不同放大率和/或畸变的影响，自动测量这些点之间的距离，并除以髁突最大内外径尺寸。为评估测量的可靠性，四名观察者评估了盘在冠状面的位置。为评估盘后3mm在冠状面闭口和张口位置的位置变化，采用配对的Wilcoxon符号秩检验。观察者间测量可靠性通过组内相关系数（ICC）进行评估。
对冠状位闭口盘位置的分析显示，在52个分析关节中的11个（21%）中，颞下颌关节盘相对于髁突处于内侧位置。在张口位置，盘的内侧位置更为常见：在34个分析关节中的29个（85%）中，盘在该平面相对于髁突处于内侧位置。盘的这种越来越内侧的位置具有统计学意义（P≤0.001）。测量可靠性评估显示结果充分（ICC≥0.7）。
在闭口和张口MR成像时，内侧位置的颞下颌关节盘似乎在正常变异范围内。当张口时，盘似乎会更向内侧移位。
