Cork and cork cambium (cork producing cell layer) are external Cortex-this is the primary tissue of the plant stem Phloem & Xylem are the inner most part and are concerned with carrying fluid and nutrients up and down the plant. Source(s): http://en.wikipedia.org/wiki/Bark. Orinoco Â· 9 years ago.
Malocclusion and bruxism are the most common causes of TMJ disorders. 1  Emotional stress is often the underlying cause of a TMJ disorder, as it can contribute to people either consciously or unconsciously tightening facial and jaw muscles and grinding or clenching their teeth.
In brief: Very common. Sure, TMJ problems can cause facial muscle spasms. It's usually the jaw muscles, on the side of the jaw (the masseter muscle) and on the side of the head or temples (the temporalis muscle) that go into spasm and cause pain from TMJ problems.