Hello, I'm Dr. Robert Fenell with HandAndFootClinicsOfAmerica.com, and I'm here on behalf of About.com today to talk to you about what muscle relaxers are.When we talk about muscle spasms as it relates to taking muscle relaxants, we are talking about skeletal muscles. There are 3 different types of muscles in the human body: 1) Cardiac muscle, which is comprised of the heart, 2) Smooth muscle, which is found in the digestive tracts such as the intestines, and 3) Skeletal muscles, which are the muscles that connect all of the bones of the body together, and cause you to ambulate and move around. A muscle spasm is an uncontrollable tightening or contraction of a muscle or muscle fiber. Muscle spasms can cause pain, tenderness and stiffness. It is common that muscle spasms can occur in the neck, shoulders and upper back, and cause neck pain and headaches. They can also be related to lower back pain, when people have muscle spasms in the lower back area, or gluteal area.Muscle spasms can be caused by acute injuries, such as an automobile accident or a slip and a fall. It can also be the result of a chronic repetitive strain or overuse injury, such as typing at a keyboard or using a screwdriver or hammer or some type of tool on a regular, ongoing basis, or doing tedious type work. Muscle spasms can also be the result of a sustained contraction due to some awkward body position over a long period of time, such as sleeping in a seated position with the head tilted to one side.The method by which muscle relaxants have their action in the muscle, it works more on the nervous system versus the muscle itself. The nervous system consists of the brain, the spinal cord, and the nerves that branch from the spine out to the individual muscles throughout the body. Muscle relaxants work at the level of the central nervous system, either the brain, the brain stem, or the spinal cord, by either inhibiting a certain nerve fiber, or stimulating the release of a certain neurochemical or hormone from the brain. This will cause the muscle to relax. There are many different types of muscle relaxers available by prescription. Be certain to consult with your primary care physician about whether or not muscle relaxers would be beneficial for your particular condition. Since every patient doesn't respond the same, your doctor may need to find out exactly the type of muscle relaxer that would be most suited for your condition.Thank you so much for watching today. To learn more, visit us online at About.com.