combustion. n. 1. the process of burning. 2. (Chemistry) any process in which a substance reacts with oxygen to produce a significant rise in temperature and the emission of light. 3. (Chemistry) a chemical process in which two compounds, such as sodium and chlorine, react together to produce heat and light.
Facet joint syndrome is an arthritis-like condition of the spine that can be a significant source of back and neck pain. It is caused by degenerative changes to the joints between the spine bones. The cartilage inside the facet joint can break down and become inflamed, triggering pain signals in nearby nerve endings.
In your spine, the bones move as far as the facet joints will allow them to before one bone forces another to stop. For example, when you stand and put your hands on your hips, bending as far backward as you can, it is the facet joints that help stop your backward movement.