Muscle twitches, also known as muscle fasciculation, are a normal occurrence. The cause behind them, however, varies. Nervous system twitches are a sign of diseases that affect the nervous system, such as muscular dystrophy or amyotrophic lateral sclerosis -- Lou Gehrig's disease. Benign twitches, meanwhile, are sporadic and are common in the eyelid, lower legs and fingers. Benign twitches can be the result of stress or poor diet.
Voluntary and Involuntary Muscles
There are different types of muscles -- involuntary, such as your heart, which move on their own without your guidance, and voluntary muscles, which require you to guide them. Twitches are found primarily in small areas of the voluntary muscles because of the amount and placement of nerves. Some are so small, they may even go unnoticed.
Muscle Anatomy
Voluntary muscles are made of up hundreds of small myofibrils that lie next to each other in a single row. This row makes up a muscle fiber. Think of it like a train with many cars. These fibers are small, and it takes many of them to create a full muscle. Fibers are connected by tissue that contains several nerves, each of which controls small sections of muscle movement. This is why twitches are usually felt only in small areas.
Nerves and Movement
With voluntary muscles, you're aware of the movement before you make it. Your brain sends an electric pulse to the nerve, which then stimulates the muscle and initiates the movement by causing it to contract. If your brain is overstimulated, it can send false or an involuntary messages to your nerves, which will still cause the muscle to contract, thus giving you a twitching sensation.
Your Brain Is In Charge
Brain and nerve activity can result in long-term muscle twitching, which is why it's a common side effect in those who suffer from nervous system diseases. Benign twitches are caused by negative effects your environment can have on the brain, which you may be able to control by removing the cause. Some examples include anxiety, drugs, caffeine and stress. Once these causes cease, the twitching usually decreases or stops altogether.
Abnormal Twitching
If you are concerned about the frequency of your muscle twitches, see a doctor. Other signs of a more serious condition are loss of feeling in a specific area, shrinking muscle and prolonged muscle weakness.
