Sagittal (A) and twin-level (B) axial T2-weighted MRI images of group 4 thumb ulnar collateral ligament Stener lesion. B, Direct approximation of adductor aponeurosis against joint capsule (small arrows). C, More proximal axial view of joint where rolled-up free end of ulnar collateral ligament (outlined in red in A, large arrows) lies proximal to free edge of adductor aponeurosis.