Lee S H, Petersilge C A, Trudell D J, Haghighi P, Resnick D L
Department of Radiology, University of California: San Diego, USA.
AJR Am J Roentgenol. 1996 Jun;166(6):1433-7. doi: 10.2214/ajr.166.6.8633458.
The purpose of our study was to define the anatomy of the extrasynovial space that cruciate ligaments occupy by examining the pattern on MR imaging of normal fluid distribution in the joints around the cruciate ligaments and correlating this distribution with histologic analysis of synovial reflections around the cruciate ligaments.
MR images of five cadaveric knees were obtained serially after larger and larger amounts of contrast material were injected into the joint space. The patterns of fluid distribution around cruciate ligaments were noted. In two other cadaveric knees, the synovial sheath around the anterior cruciate ligament was injected directly with contrast material under CT guidance. Anatomic and histologic correlation was made with findings on corresponding MR images.
The pattern of fluid distribution is bounded by the synovial reflections around cruciate ligaments. When maximum joint distention is achieved, fluid almost surrounds the cruciate ligaments. The area without fluid is a triangular space between the anterior and posterior cruciate ligaments that appears on the midsagittal image. This triangular space of the cruciate ligaments is an extrasynovial space within which both the anterior cruciate ligament and the posterior cruciate ligament reside.
The overlying synovial membrane of the cruciate ligaments does not normally allow joint fluid to enter the substance of the ligaments or the triangular space of the cruciate ligaments. Therefore, fluid collections seen on MR imaging in these extrasynovial spaces or structures likely arises from injury to the cruciate ligaments.
我们研究的目的是通过检查交叉韧带周围关节内正常液体分布的磁共振成像（MR）模式，并将这种分布与交叉韧带周围滑膜折返的组织学分析相关联，来明确交叉韧带所占据的滑膜外间隙的解剖结构。
向五个尸体膝关节的关节腔内依次注入越来越多的对比剂后，连续获取MR图像。记录交叉韧带周围的液体分布模式。在另外两个尸体膝关节中，在CT引导下直接向前交叉韧带周围的滑膜鞘内注入对比剂。将解剖学和组织学结果与相应的MR图像所见进行关联。
液体分布模式由交叉韧带周围的滑膜折返界定。当关节达到最大扩张时，液体几乎包围交叉韧带。无液体的区域是在矢状面图像上出现的前、后交叉韧带之间的三角形间隙。交叉韧带的这个三角形间隙是一个滑膜外间隙，前交叉韧带和后交叉韧带均位于其中。
交叉韧带上方的滑膜通常不允许关节液进入韧带实质或交叉韧带的三角形间隙。因此，在这些滑膜外间隙或结构的MR成像上看到的液体积聚可能源于交叉韧带损伤。
