Fig. 5. Injury to the intersesmoidean ligament with adjacent osseous abnormalities (B) of the proximal sesamoid bones is seen as well in the corresponding radiographs (A). Abnormalities are seen in the proximal ISL (arrow) at the level of the suspensory ligament branches (C) as well as at the level of the sesamoid bones.
tected with ultrasound consists of focal circular to oval regions of fiber disruption and/or fiber abnor- mality that can be identified immediately distal to the sesamoid bones (Fig. 6). The regions of abnor- malities are typically located medially or laterally, and more often both the medial and lateral aspects are affected but to differing degrees.
6. Conclusions
Ultrasound is a useful imaging modality for the diag- nosis of injury to the ISL and SSL. MRI will still be required to diagnose certain injuries affecting the ISL and SSL. However, with an understanding of the normal anatomy, anatomical variations, and the
Fig. 6. Corresponding MRI and ultrasound images from three cases with injury to the proximal extent of the SSL at the transition with the ISL compared with normal anatomic reference image at this level. These images demonstrate the typical appearance of injury to the SSL at this level with focal circular to oval regions of fiber disruption and/or fiber abnormalities that can be identified immediately distal to the sesamoid bones. Focal hyperechogenic regions are consistent with fibrosis or mineral that is not dense enough to prevent the ultrasound beam from continuing through the tissues. As demonstrated by these cases, the regions of abnormalities are typically located medially or laterally within the ligament, and both the medial and lateral aspects can be affected, but often to differing degrees. A gross image is provided to demonstrate a normal anatomic representation of the SSL.
