Forearm Muscles Anatomy

The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in anatomy, technically, means only the region of the upper arm, whereas the lower “arm” is called the forearm.

The muscles in the forearms are numerous and complex. For the most part, they are polyarticular muscles. In strength training, you will focus on the following muscles:

• Brachioradialis – which flexes the arm when the hand is pronated;
• Wrist flexors – which lift the hand when it is pronated;
• Wrist extensors – which lift the hand when it is supinated;

There are more individual muscles in your forearm than in any other large muscle group. The forearm is a mass of some 20 different muscles. It has two separate muscle compartments: the flexor group on the palm side and the extensor group on the reverse side. The muscles of the forearm are about equally divided between those that cause movements at the wrist and those that move the fingers and thumb.

A good brachioradialis muscle has numerous advantages: (a) it considerably increases the size of the forearm; (b) it fills the gap that might exist between the forearm and a short biceps, and, (c) it protects the biceps from injury.

The lower arm, or forearms, are an often neglected muscle group. A well-muscled forearm isn’t as eye-catching as big biceps, but you need that strength, especially if you’re doing serious lifting and need to maximize grip strength. They are essentially impossible to hide and unlike biceps you don’t have to roll up your sleeves for people to see them! Forearms are almost always visible. They can be your greatest ally or your most dreadful foe.

They should be trained after the biceps and typically in the same workout because of the proximity of the biceps and forearms and because the forearms assist on biceps exercises. The major exercises for below the elbow are reverse curls (similar to standard curls, only with palms-down grip) and wrist curls. Hammer curls (in which the palms face each other) actually train both the biceps and the forearms and are good bridge between biceps and forearm exercise.

The lower arms have several muscle groups that move the wrist: supinators, pronators, flexors, and extensors.

• Wrist supinators turn the hand from a palms – down to a palms-up position.
• Wrist pronators turn the hand from a palms-up to a palms-down position.
• Wrist flexors bring your hand toward your forearm.
• Wrist extensors pull your hand away from your forearm.

Some of the lower arm muscles get a decent workout during upper arm exercises. But if you really want to make them pop, you need to train them more directly with dedicated exercises.

Roles of the Forearms

The muscles in the forearms act in the following ways:

• On the hand by closing, opening, and turning it
• On the wrist by raising and lowering the hand
• On the elbow by raising and lowering the forearm

Practical observations: the forearm, a muscle of extremes

The forearms are full of paradoxes:

• Some people have enormous forearms even without strength training.
• Others have modest muscle mass despite efforts to develop the forearms.
• Even with very little muscle mass, some people are capable of extraordinary feats of strength with their hands, such as twisting nails easily.

Whether it will be easy or difficult to develop your forearms is closely linked to the length of the muscles:

• The longer the muscles in the forearm are (and therefore the shorter their tendons are), the easier it will be to develop them. This does not mean that your forearm muscles are really strong; it means that you have good leverage. However, with muscles that are very long and well developed, you can have weak hands. In this case, it does not mean that your muscles are weak; it means that you do not have good leverage.
• The shorter the muscles are, the more difficult it will be to develop them. Unfortunately, you cannot lengthen a muscle because length is determined by genetics.

Closing thoughts

The forearms participate in almost all arm and torso exercises. Their strength can prove to be a limiting factor in many exercises and numerous sports. If they are weak, then you need to strengthen them.