MR imaging of anatomy and tears of wrist ligaments.

Numerous intrinsic and extrinsic wrist ligaments are visible at magnetic resonance (MR) imaging. Because the previously published descriptions of these ligaments were often conflicting, the authors derived a classification system based on a functional perspective and their experience with MR imaging, arthroscopy, and surgical dissection. This system was used to evaluate MR images of 23 cadaveric wrists for the presence and integrity of 16 wrist ligaments. MR images were prospectively analyzed by two observers, and all findings were correlated with the results of arthroscopy. The best detection rates and diagnostic confidence rates were achieved for the triangular fibrocartilage (100% and 100%, respectively) and the scapholunate ligament (91% and 87%, respectively). Other ligaments were less well seen, partly because of their size and course. Eighty-two percent of the triangular fibrocartilage tears, 50% of the scapholunate tears, and 40% of the lunotriquetral tears seen at arthroscopy were detectable on MR images. Identification of these three types of tears on MR images is important because they are functionally significant and because there are accepted methods of treating them in orthopedic practice.