Triceps start from the shoulder on the back side of upper arm and end at elbow. Triceps have three small sections that create the whole muscle group. Triceps make up almost two-thirds of the muscle mass on your upper arm. The main function for triceps is to extend elbow. It is used in variety of sports, like different games where you throw ball or in boxing.
There are many different exercises for exercising triceps. The basic idea when exercising triceps is to keep your elbow stationary and let the triceps do all the work.