The forearm muscles are located between the wrist and elbow, the terms is used loosely to describe the entire appendage on the upper limb. Even though there are many muscles involved in the forearm area, the basics consist of two - the extensors and flexors. The first is responsible for the flexion and the later for extention movements of the wrist.
The forearm muscles are usually rarely exercised on their own, which is not really an issue as most exercise that require some type of a grip always involve this muscle. Therefore, even though they may not be regularly exercised as part of a regular routine, they are a secondary muscle in many exercise. We do however recommend that some type of forearm exercise be included into your weight training plan as no muscle group should be neglected for a well rounded physique.