膝关节半月板根部MRI影像解剖

目的 总结半月板根部的MRI解剖特点,确定半月板主体部分与根部的分界。方法 收集2012年10月—2014年2月保定市第一中心医院骨科24例经关节镜证实正常半月板根部的膝关节MRI资料和1例男性成人患者因下肢动脉硬化而截肢的新鲜膝关节标本,对半月板根部的MRI解剖行前瞻性研究,总结半月板根部MRI的形态、走行及附着点的位置,分析信号特点,并测量根部的长度、宽度、高度以及各根部走行角度。另在新鲜膝关节标本上确定半月板主体部分与根部的分界并用铜丝标示之,对标本行MRI扫描。结果 24例患者膝关节MRI显示:内侧半月板后根部呈梳状斜向下走行,信号较半月板主体部分稍高,附着于髁间后区;外侧半月板后根部较内侧半月板后根部明显长,走行于髁间隆起,附着于内侧髁间隆起的外侧面,信号与半月板主体部分类似;内侧半月板前根部较细,附着于髁间前区最前缘,为低或较低信号;外侧半月板前根部呈梳状稍向下向后走行,信号稍高,附着于髁间前区并稍向外下方倾斜的骨表面。各根部测量数据显示:横断面外侧半月板后根部最长,为(15.74±2.03)mm;冠状面内侧半月板后根部最短,为(7.88±1.57)mm;外侧半月板后根部走行与标准冠状面扫描线的夹角角度最大,为34.00°±9.24°。1例新鲜标本MR扫描图片清晰,半月板主体部分与根部分界标记显示清晰。结论 内外侧半月板前后根部各有其特点,MRI能够清晰显示半月板根部的形态、走行、信号特点及附着点位置。

MRI anatomy of the meniscal roots of knee

Objective To summarize the MRI anatomy of meniscal roots, and to determine the delimitation between meniscal main body and roots. Methods Knee of a male adult patient with amputation due to arteriosclerosis of lower extremity MR images of normal meniscal roots of 24 patients confirmed by arthroscopy and 1 fresh knee joint specimen were collected from October 2012 to February 2014. MRI anatomy of the meniscal roots of knee were studied prospectively. The dimension, courses, insertion sites and signals of meniscal roots were analyzed. Length, height, width and course angles of the meniscal roots were measured. To determine the delimitation of meniscal main body and root in the fresh knee joint specimen, then the specimen was studied with MR exam. Results The posterior root of medial meniscus inclined downward, which were attached to the posterior intercondylar area. Its comblike signal was slightly higher than that of meniscal main body. The posterior root of lateral meniscus run at the intercondylar eminence was obviously longer than that of medial meniscus, and attached to lateral surface of the medial intercondylar eminence. Its signal is similar to that of meniscal main body. The anterior root of medial meniscus attached to the most anterior border of the anterior tibia intercondylar area, and its signal was lower or slightly lower. The anterior root of lateral meniscus coursed downward and backward, and attached to the anterior intercondylar area and the surface of the bone sloping outwards and inferiorly. Its signal was slightly hyperintense and comblike. MR images of fresh knee joint specimen and the delimitation marker of meniscal main body and root were clear. The longest part was the posterior root of lateral meniscus, which was (15.74±2.03)mm, the shortest part was the posterior root of medial meniscus, which was (7.88±1.57)mm. The posterior root of lateral meniscus had the maximum course angle, which was 34.00°±9.24°. Conclusions The MR features of the four meniscal roots are different from each other. MR imaging is a relatively good method to show the meniscal roots and display clearly the features of the dimensions, courses, signal, and insertion sites of meniscal roots.