Stener like lesion.

The image on the left obtained through the midportion of the thumb metacarpophalangeal joint demonstrates a normal low signal ulnar collateral ligament (white asterisk).  In contrast, the radial collateral ligament is absent and replaced by hyperintense signal (red asterisk). The sagittal band is well seen since it is outlined by edema (arrowhead).  The image on the right is more dorsally located and demonstrates the radial collateral ligament at the metacarpal origin but with the torn end of the ligament oriented proximally and radially (arrow), located proximal to the radial sagittal band (arrowhead).

Axial STIR images at the level of the little finger metacarpal head confirm the findings.  The left image demonstrates the normal ulnar collateral ligament (white asterisk), edema instead of the ulnar collateral ligament (red asterisk), and the intact radial sagittal band (arrowheads).  The right image obtained proximal to the left demonstrates the dorsally and radially folded radial collateral ligament which remains attached at the metacarpal head.