A tooth (plural teeth) is a small, calcified, whitish structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are covered by gums.
Symptoms can include: 1  A popping sound (or a popping or snapping feeling) at the time of injury can sometimes be heard (or felt) if a ligament is completely torn. 2  Swelling of your knee. 3  Pain in your knee.  Tenderness around your knee on 1  touching. Not being able to use or move your knee normally.
There are four main ligaments in the knee that can become injured. During injury, a knee ligament may be stretched (sprained), or sometimes torn (ruptured). Ligament rupture can be partial (just some of the fibres that make up the ligament are torn) or complete (the ligament is torn through completely).