A spasm is an abnormal involuntary muscle contraction such as a twitch or cramp that is accompanied by pain and/or interference with normal function. Cramp-like spasms of muscles are called tetany. Additional Info: Spasms can have a number of causes. For example, back pain and spasms can be caused by a strain, sprain or injury. Other spasms can be caused by pinched nerves, for example, a hemifacial spasm (one affecting one side of the face only) is caused when an artery presses on one of the facial nerves that controls the muscles on that side of the face. The science of ergonomics looks at the relationship of man and his work, incorporating the anatomic, physiologic, and mechanical factors involved to achieve safety and efficiency. Following good ergonomic principles can avoid many common workplace injuries such as back strain, carpal tunnel syndrome, and more. See: The links under Further Reading for basic ergonomic principles and more. MSDS Relevance: This term usually appears on MSDS's as a symptom of exposure. Exposure to certain chemicals can cause spasms or tremors. If these involve the heart, the condition can be life-threatening. Read the MSDS's of the chemicals used in your workplace before you use them for the first time. Know if any of them have the potential to cause spasms so you can recognize the spasm as a symptom of exposure. See also: Myalgia, Nystagmus