Pathology of Extrinsic Ligaments: A Pictorial Essay

Abstract

The role of the extrinsic ligaments, together with the intrinsic ligaments, appears to be much more important than previously thought in the setting of carpal stability. The anatomy and pathology of the extrinsic wrist ligaments is complex. Magnetic resonance imaging (MRI) with thin slices is essential for visualization. This article describes the pathological appearance of the extrinsic palmar and dorsal radiocarpal and ulnocarpal ligaments on MRI, correlated with arthroscopy (performed by two skilled hand surgeons), clinical findings, and follow-up. High-resolution MRI, especially using isotropic three-dimensional sequences with orthogonal multiplanar reconstructions on 3T MR systems, allows detailed depiction of many of the extrinsic ligaments affected in carpal injuries. Recognition of ligament abnormalities is improved by intra-articular or intravenous injection of contrast before the examination. Both techniques may help to determine the precise localization, size, and extent of dorsal and palmar radiocarpal and ulnocarpal ligament lesions. Further experience with these techniques is needed to define the place of MRI in the management of traumatic wrist injuries.

Advanced imaging of the scapholunate ligamentous complex

“…Because most of the carpal ligaments have an oblique or curved course in 3D space, they often cannot be depicted in their entirety from origin to insertion, and image interpretation is based on the summation of adjacent MR slices. By applying 3D techniques with 0.5-mmthick slices such as 3D dual echo with steady-state precession (DESS) or fat-saturated 3D proton density (PD)-weighted sequences, this drawback could be overcome by post-processing isotropic datasets in an anatomical way [36]. Until now in the literature, few studies of MRA on 3 T compared to arthroscopy have been published, based on a small series of patients with poor sensitivity and specificity rates [37,38].…”

“…It may be visualised on 2-mm-thick MR images obtained in the axial plane using T1 or PD spin echo sequence or better on 0.5-mm-thick contiguous axial reconstructions from 3D DESS or fat-saturated 3D PD sequences. It usually presents a dark hypointense signal and a slightly oblique course on axial views [36] (Fig. 3).…”

“…Palmar ligaments are thicker and stronger than dorsal ligaments. Functionally, the ligaments can be divided into three reversed V-shaped groups, two on the palmar side and one on the dorsal side [36,55]. All radiocarpal ligaments have a proximal origin at the distal end of the radius and a distal insertion at the level of one or more carpal bones.…”

“…It helps to stabilize the lunate dorsally and limits the extent of ulnar translation of the wrist. The ligament is most often well visualized on thin coronal 3D images [36,57,58].…”

“…Since it runs superficial to the SLIL, it is used by surgeons as an arthroscopic landmark to help locate the SLIL, which may be difficult to identify. It can sometimes obscure the anterior part of the radiocarpal joint like a veil, especially when a synovitis is present [36,63] (Fig. 7).…”