1. Kick a ball too hard=HYPER-EXTENSION may have a popping sound
   1. S/S popping sound & Unstable knee
      1. Ant. Cru. Lig. Injury
         1. Positive lichmann's test & positive anterior drawer test
2. Hit the dash board with your knee in an accident(uncommon) has little pain and little decrease in function
   1. Pot. Cru. Lig. Injury
3. valgus (away from midline aka abduction) strees
   1. medial colla. lig inj.
4. VARUS STRESS =adduction(uncommon)
   1. lateral col. lig. inj.