The T sign is seen on a coronal T2 or fat-saturated intermediate-weighted MRI of the elbow. It refers to the interposition of joint fluid between the ulnar insertion of the ulnar collateral ligament and the sublime tubercle and indicates a partial undersurface tear of the distal anterior bundle of the ulnar collateral ligament 1,2. Recurrent trauma causes micro-tears of the ulnar collateral ligament, resulting in deterioration and rupture of the ligament 3.
Practical points
In the setting of a previous surgical reconstruction, a T sign is usually consistent with a normal graft insertion and does not necessarily reflect a partial graft tear 1.
This is not to be confused with the T sign of a monochorionic multifetal pregnancy.