What are the Muscles in your Arm to Target During Workouts?

Which muscles are we targeting during arm exercises with or without equipment? Your arm from the hand and wrist to your shoulder has multiple muscles.

The movement of arms is determined by the chest and shoulder muscles. The chest, upper back and shoulder muscles are not usually considered as arm muscles. However, they are vital to virtually every movement or stabilizing force when the arm is used to perform tasks.

When performing workouts such Arm Exercises with Resistance Band or Resistance Band Exercises for a great Arm, you need to know exactly the arm muscles you are targeting to build. So what are the muscles of your arm? I will start by glancing at the muscles of the arm and upper back, shoulder & chest muscles before going on the arm muscles.

Arm Muscles

The major arm muscles and their functions are

  • The Biceps Brachii are responsible for the movement of the elbow. They also cause the external rotation of your forearm and hand.
  • The Triceps Brachii is responsible for stretching your arm by extending your elbow, shoulder and your arm’s movement behind you. The triceps have 3 different heads that each starts at the shoulder, spanning through the back of your arm to the elbow.
  • The Brachialis span from the middle of the upper arm to just below your elbow. This strong elbow flexor is responsible for flexing your elbow.
  • Coracobrachialis starts from the shoulder and span to the middle of your upper arm until just below the elbow. It also helps in flexing (raising) of your upper arm.

To strengthen your arm target as many of these muscles you can to get enough and proportional strength directions of motion of your arm.

forearm muscles


What Are The Muscles Of Your Arms?

Your upper arm and forearm (area between elbow and wrist) have over 20 muscles. However, the 4 major muscles of the arm are biceps, triceps, forearm flexors and forearm extensors. The other muscles support these 4 major muscles.

How do you locate these muscles in your body? Standing with your arm by your side and palm rotated forward, looking down on the arm, you see the front or anterior muscles of your arm. Opposite those anterior muscles are the back or posterior muscles of your arm.

The front or anterior arm muscles

These muscles are flexors and pull the extremities inwards towards your center. The upper arm biceps bend or flex the elbow while the flexors of the forearm bend your wrist and fingers.

The back or posterior arm muscles

The extensors are found on the back of your arm and play the opposite role to the flexors. While the triceps straighten or extend your elbow, the forearm extensors straighten your wrist and fingers.

From here, let’s go into detail on each particular muscle of both the upper arm and the forearm, locating it and stating its functions. Where are the upper arm muscles located? Where are the forearm muscles located?

arm muscles

Anatomy of the Upper Arm Muscles

The Biceps Branchii

The biceps may look like a muscle lump but it comprises 2 long heads (sheaths): long and short, which originate from 2 points near the shoulder joint. They then merge to form an attachment point at the top of your forearm.

In a standing position, your arms by your side and your palm rotated forward, the long head of the biceps lies far away from the torso. The biceps originates from the superglenoid tubercle, which is the outermost shoulder bone that lies below the deltoid muscle.

The biceps tendons join between 2 lumps (tuberosities) in shoulder bones. This is the bicepital groove, a common site for injuries and becomes inflamed when overstressed.

The short head of the biceps starts from the coracoid process or tendon at the shoulder blade. The coracoid process is visible over the top of your shoulder from the front view. Interlacing your hands behind your back, straightening the arms and squeezing your shoulders, stretches this tendon and hence your biceps.

Halfway the upper arm, the 2 sheaths or heads converge and meet in a single tendon that joins with the inside edge a bone called radius. The radius runs on the thumb side of the forearm.

As a heavyweight lifter, you can realize that this tendon is torn when your biceps bunches outwards

The Functions

The 2 sheaths or heads of the biceps have 2 main functions, namely:

  • Hand supination. That is they are responsible turning the hand in a palm-up or palm-down position.
  • They close or flex the elbow joint when curling a weight up

Building the Biceps

Your biceps are built and strengthened when you do pulling motions in palm-up positions. For instance, during pull-ups, pull-downs or rows.

The Brachialis

The Brachialis is a long, flat muscle that lies beneath the biceps and gives it shape and height. An athlete’s nice-looking muscle ridges on the upper arm are thanks to the brachialis.

It originates from the outside front section of the upper arm and joins with the ulna of the forearm.

The Functions

Though the biceps get the credit, however because of its position and size, the brachialis is actually the strongest flexor muscle of your elbow

Building The Brachialis

You build your brachialis by pull-ups, pull-downs or row with your hands parallel. You also do it with hammer dumbbell curls with your hands facing each other.

The Coracobrachialis

Just like the short head of the biceps muscles, the coracobrachialis originates from the coracoid process and runs inside the short head of the biceps. It joins to the inside of the humerus and is active when you squeeze the upper arms inwards and down towards the torso. For instance, when performing dip exercises.

The Triceps

As its name suggests, triceps are a 3 headed muscle at the back of your upper arm. The 3 heads of the triceps are: long head, lateral head, and medial head. Each head originates from a distinct point.

  • The long head originates from the shoulder blade or scapula. It then crosses the shoulder and elbow joints to end at the olecranon. This muscle is stretched when you reach your hand overhead, bending your elbow.
  • The lateral head originates from the humerus and merges with other triceps heads about 2/3 way down the upper arm before continuing to end at the elbow. They form a comma-shaped notch at the outside of the upper arm.
  • The medial head originates from the back of your upper arm bone about 2/3 way down from your shoulder. It then runs at the back of your upper and merges with the other heads at the elbow. This is the deepest of the triceps muscles.

Similar to the biceps tendon, the triceps tendon can rupture at the elbow and bunch up towards the shoulder. This makes straightening the arm difficult or even impossible.

The Functions

The triceps extend your arm at the elbow join. Their role is the exact opposite of the biceps.

Building The Triceps

You build up your triceps by performing compound movements with your arm under load. For instance bench presses, overhead presses and push-ups.

Another way is to do triceps push-downs, kickbacks and overhead triceps extensions.

Arm Muscles

Anatomy of the Forearm Muscles

The forearm muscles are divided into 2 groups: the flexors which lie in the inner side of the forearm and responsible for the bending of the wrist forward. The extensors which lie on the outer side of your forearm and bends the forearm outwards.

1. The Forearm Flexors

When you stand with your arm by your side and palm facing forward, you see the elbow knob or funny bone closest to your body. When the flexor muscles are overworked, it can lead to Golfer’s elbow or inflammation in the elbow knob.

The forearm flexor group comprises 3 layers of muscles, the main one being the superficial group. It originates from the funny bone and consists of the flexor carpi ulnaris, pronator teres, the flexor carpi radialis and the palmaris longus. All these muscles, which are long and cable-like, cooperate in pronating and flexing the wrist.

Immediately below the superficial group of muscles are many muscles that help in articulating the movements of fingers and thumb. The prominent of this is the flexor digitorum superficialis. It tapers into 4 small tendons that pass through the space below the band of tissue at the base of the palm. Another layer of muscles runs up the palms and joins your fingers to enable flex.

The Function

The forearm flexors or anterior muscles inside the arm flex the wrist forward and turn the hand in the palm-up or palm-down positions.

Building The Forearm Flexors

Exercises that challenge the grip like rows, curls, pull-ups or farmers walks workout your forearm flexors and build them up. Hanging from a bar, performing wrist curls or working with a spring-loaded gripper focuses more on the forearm flexors.

upper arm muscles

2. The Forearm Extensors

Stand with your arm by your side and the palms forward. The forearm extensors originate from the outermost knob on your elbow. This point of attachment will develop lateral epicondylitis or inflammation if overstressed.

Similar to the flexors, the extensors are long and run along the forearm and attach at the fingers. The largest of the extensors is the brachioradialis, which originates from the upper arm and attaches on the outside of the wrist. It is responsible for the bending of the elbow; hence, it acts like a flexor in the same way as the biceps instead of an extensor.

Then we have next to the brachioradialis many smaller similar muscles that help the wrist to rotate and extend. These muscles are the extensor carpi ulnaris, extensor carpi radialis, and the extensor carpi radialis longus.

The extensor digitorum and the extensor digiti minimi help in opening of your hand. All manner of intricate, subtle movements of the fingers and thumb are because of several neural and muscular pathways running into and out of them.

The functions

The forearm extensors aid in the extension of the fingers, wrist, thumb and turning of the palm-up known as supinating.

Building the forearm extensors

You develop the forearm extensors by performing curls, pull-ups and rows with an underhand grip. You can also work them directly with a light dumbbell.  Or you draw your fingers together and wrap them with a tight rubber band. Then extend the fingers against the pulling force of the rubber band.

Single-arm triceps extension with a band

Upper Back, Shoulder & Chest Muscles

  • The Pectoralis Major, also called simply as the pec major is responsible for pushing, lifting and bringing the arm down, and most movements of the arm. It also cross-link the arm from a horizontal position and helps in the rotation of the upper arm.
  • The Pectoralis Minor is a Scapular Stabilizer
  • The Posterior Shoulder Muscles handles pull-apart movements by moving the upper arm backwards.
  • The Deltoids are located around the front, side and back of your shoulder. They rotate the arm and move the arm upwards in all directions.
  • The Rotator Cuff Muscles are shoulder stabilizing muscles, which also help to start arm movement.
  • The Latissimus Dorsi is the upper back muscle causes the downward or backward movements of your arm. For instance, in rowing motion or lat pull down.

FAQs about arm muscles

What are the 3 muscles in your arm?

Your arm has so many muscles, but the 4 major muscles of the arm are:

    • The biceps brachii, which is a 2-headed muscle on the anterior or front side of the humerus.
  • The brachialis, which is underneath the biceps
  • The coracobrachialis, which is at the upper anterior part of your arm near the shoulder
  • The triceps at the back of your upper arm: The 3 heads of the triceps are: long head, lateral head, and medial head. Each head originates from a distinct point.

What are the main muscles in the arm?

The major muscles of the arm are the biceps, the triceps, the brachialis, the coracobrachialis and the anconeus.

But which muscles supinate the forearm? The biceps brachii, the supinator muscle and the biceps brachioradialis all contribute to the forearm’s supination and the palm.

How many muscles are in your arm?

About 20 muscles are in the arm.

What conditions or disorders affect the arm muscles?

Muscle strain and Rhabdomyolysis. When the arm muscles stretch too far beyond the elastic limit, muscle strain can occur in which your muscle can rupture or tear. For instance, during weight lifting.

A rare condition that is common with endurance athletes when the muscle fiber breaks down is called Rhabdomyolysis

What are some common signs and symptoms of conditions affecting the arm muscles?

Healthcare providers usually look for following conditions when doing physical examination for arm muscle injuries.

  • Muscle cramps or spasms
  • Muscle pain
  • Muscle weakness or reduced range of motion
  • Tenderness and swelling in the arm

What are some common treatments for arm muscles injuries?

  • Massage therapy
  • Acupuncture and dry needling
  • Medications: like nonsteroidal anti-inflammatory drugs (NSAIDs)
  • RICE(Rest, Ice, Compression and Elevation) method
  • Physical therapy
  • Surgery
  • Stretching

How can I keep my arm muscles healthy?

Take the following precautions during arm workouts:

  • Warm up before workouts is very important. Stretch and warm up the arms before exercising.
  • escalate the intensity of the workouts.
  • Do not lift too heavy things and stop if you feel too much pain

When should I call a doctor about my arm muscles?

Call your healthcare provider if you have:

  • Muscle pain and weakness
  • Muscle tenderness and swelling
  • Muscle weakness or reduced range of motion
  • Numbness and tingling
  • Very dark, red or brown urine.

Wrapping Up

The arm muscles help in the movement of the fingers, thumb and arm. There are several arm muscles in the upper arm and forearm. These muscles control precise movements such as writing and eating, but they also allow you to do big movements like throwing a baseball.

To avoid injuries, always warm up before arm workouts. Avoid over stretching the muscles and stop the exercise when the muscles become too painful.

Look for your healthcare provider when the muscles are painful, weak, swelling, numbness or tingling.


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