| Metacarpophalangeal joint injury | ||
| Collateral ligament injury | Radial | Stable |
| Unstable (complete disruption) | ||
| Ulnar | Stable | |
| Unstable (complete disruption) | ||
| Sesamoid Fracture | ||
| Dislocation | Simple | |
| Complex | ||
Ligament injuries may also be additionally classified by the maximum angle of deviation and by the percent of joint surface uncovered in xrays taken while the joint is placed under stress.