<s>[INST] Hi, I have been having a twitch on my left thumb on and off for 3 months or so. I am a dental hygienist but I am right handed. I feel a little week on my left hand. It s starting to weird me out. I did separate my left shoulder a month ago too. Any thoughts? [/INST] Hi, Thanks for your query. It seems that you have muscle twitches or articulations. These are small, local, involuntary muscle contraction and relaxation visible under the skin arising from the spontaneous discharge of a bundle of skeletal muscle fibers. You might consult your doctor who can order 1. A few blood tests including thyroid function tests, 2. Serum electrolytes including Serum calcium and potassium levels. 3. Serum B12 levels In case the above tests are normal further testing can be done including - nerve conduction studies, Electromyography, etc. These tests might help to diagnose any underlying neurological issues. I do hope that you have found something helpful, and I will be glad to answer any further query. Take care </s>