Sudden hand cramps are mainly due to the dysfunction of the flexor muscles of the forearm, and the corresponding spastic contraction of the muscles on their own, resulting in hand cramps. The causes are often the following: a. Acute injury to the forearm muscles, due to excessive activity causing muscle damage, or due to direct violent trauma, resulting in injury to the flexor muscles of the forearm, muscle dysfunction will appear uncontrolled muscle contraction, resulting in finger cramps. Second, chronic strain injury, due to overload activities or long-term sports, resulting in corresponding strain injury to the forearm muscles, can produce sterile inflammation. When the inflammation is stimulated, it will also produce muscle dysfunction and finger cramps symptoms. Third, under the stimulation of certain acute adverse factors, resulting in muscle dysfunction, such as acute cold, moisture or other adverse stimuli, physical and chemical factors, can lead to muscle dysfunction and the appearance of sudden finger cramps.