Arm Muscles

You have many muscles in your upper arm (between your shoulder and elbow) and forearm (between your elbow and wrist). These upper muscles work together to help with big and small arm movements. Your forearm muscles control your fingers and thumbs, helping you with delicate tasks like threading a needle.


What are the arm muscles?

You have more than twenty muscles in your upper arm and your forearm (the area between your elbow and your wrist). Your arm muscles help you with small, precise (fine motor) movements, such as wiggling your fingers or fastening a button. They also allow you to do big movements, like straightening your elbow, raising your arms above your head or doing push-ups.

Some muscles sit deep inside of your arm. Others are close to the surface of your skin, and you can easily see their outline when you contract (flex) your muscle. Tendons (soft tissues) attach your muscles to bones in your arm and shoulder.

Arm muscle strains (tearing or stretching a muscle too far) are common injuries. They often result from overuse or by lifting an object that’s too heavy. To avoid an arm muscle injury, warm up before exercising and stop if you feel pain.


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What is the purpose of the arm muscles?

The muscles in your upper arm and forearm allow you to move your arms, hands, fingers and thumbs. Different muscles help with precise movements, such as threading a needle, as well as big movements like throwing a ball.

What is the purpose of the forearm muscles?

Muscles on both the underside and the top of your forearm allow you to:

  • Bend, flex and extend your wrist and fingers.
  • Move your hand toward your body and turn your hand away from your body.
  • Turn the palm of your hand to face down.

Muscles located deep inside of your forearm have several jobs:

  • Controlling the top joints in your fingers.
  • Moving your thumb joint.
  • Turning your palm to face up or down.


What is the purpose of the upper arm muscles?

Your upper arm muscles help you move your arms. They have different jobs based on their location. They help you:

  • Bring your arm toward your body.
  • Extend (straighten) your forearm at your elbow.
  • Flex your arm at your elbow (bring your hand to your ear).
  • Move the top part of your arm at your shoulder.
  • Raise your arm above your head.
  • Turn the palm of your hand to face up.


Where are the forearm muscles located?

You have many muscles in your forearm (between your elbow and your wrist). Some of these muscles are in the top and some are on the underside of your forearm. Your forearm muscle anatomy includes:

Superficial forearm muscles

You have several muscles on the underside of your forearm that are superficial (close to your skin’s surface). Most of them start below your elbow and extend to your wrist. They are:

  • Flexor carpi ulnaris.
  • Palmaris longus. (Up to 25% of people don’t have this muscle.)
  • Flexor carpi radialis.
  • Flexor digitorum superficialis.
  • Pronator teres.

Superficial muscles on the top of your forearm include:

  • Anconeus.
  • Brachioradialis.
  • Extensor carpi radialis longus and brevis.
  • Extensor digitorum communis.
  • Extensor digiti minimi.
  • Extensor carpi ulnaris.

Deep forearm muscles

These muscles sit under the superficial muscles on the underside of your forearm. They are:

  • Flexor digitorum profundus.
  • Flexor pollicis longus.
  • Pronator quadratus.

Muscles located deep under your skin on the top of your forearm are:

  • Abductor pollicis longus.
  • Extensor pollicis brevis.
  • Extensor pollicis longus.
  • Extensor indicis.
  • Supinator.


Where are the upper arm muscles located?

You have four muscles in your upper arm, which is the area between your shoulder and your elbow. Your upper arm muscle anatomy includes:

  • Biceps brachii. Your biceps muscle is in the middle of your upper arm. It’s a superficial muscle because it’s close to your skin’s surface.
  • Brachialis. This deep muscle sits underneath your biceps.
  • Coracobrachialis. Also deep under your biceps, this muscle connects to your scapula (shoulder blade).
  • Triceps brachii. Your triceps muscle is on the back of your arm, just above your elbow. Like the biceps, your triceps muscle is just under your skin’s surface.

What do the arm muscles look like?

Your arm muscles are part of your musculoskeletal system. They’re a type of muscle called skeletal muscle. Many individual fibers make up skeletal muscles. These fibers bundle together to create a striated, or striped, appearance.

Conditions and Disorders

What conditions and disorders affect the arm muscles?

A few conditions that affect your arm muscles include:

  • Muscle strain: Injuries to your arm muscles can happen when the muscle fibers stretch too far. In severe cases, your muscles can rupture (tear). You can pull or tear an arm muscle by lifting a heavy object or from rigorous activities. Muscle strains are very common. They can also result from overuse.
  • Rhabdomyolysis: This rare, life-threatening condition happens when muscle fibers break down. Rhabdomyolysis (rhabdo) usually results from overexertion and strenuous exercise. It’s more common in endurance athletes.

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

Problems in your arm muscles can cause:

  • Muscle pain, tightness and stiffness. The pain may be sharp or dull. It may start out as mild and slowly worsen.
  • Muscle weakness or decreased range of motion.
  • Spasms or muscle cramps.
  • Tenderness or bruising in your arm.

Healthcare providers can usually diagnose muscle strains during a physical examination. Your healthcare provider will look for swelling and tenderness. They may move your hand, fingers or arm.

To check for damage to your muscle, tendons or other soft tissues, your healthcare provider may order an imaging study, such as ultrasound or MRI. These imaging studies help your healthcare provider make an accurate diagnosis.

What are some common treatments for arm muscle injuries?

Depending on the location and severity of the injury, your healthcare provider may recommend:

  • Acupuncture: Dry needling and acupuncture can reduce acute (short-term) and chronic pain from muscle injuries. These treatments can also speed up the healing process.
  • Massage therapy: Massage can help you recover from a muscle strain injury. It can also increase flexibility and range of motion while relieving pain.
  • Medications: Your healthcare provider may recommend over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) or prescription pain-relief medications.
  • RICE method: You may be able to treat minor muscle strains and tears with rest. Ask your healthcare provider about the RICE method (rest, ice, compression and elevation). Apply ice or a cold compress every 20 minutes or so to relieve pain.
  • Physical therapy: After a muscle strain or tear, a physical therapy (PT) program can strengthen your arm muscles. Your healthcare provider will tell you when you’re ready to start a PT program after an injury.
  • Stretching: Gentle stretches can relieve pain and tightness from a pulled muscle. Ask your healthcare provider to recommend stretches.
  • Surgery: If you have severe muscle tear, your healthcare provider may recommend surgery.


How can I keep my arm muscles healthy?

To avoid problems with your arm muscles, you should take time to stretch and warm up before using them. Warm muscles are less likely to stretch too far or tear. When exercising, increase the intensity gradually. Avoid lifting anything too heavy, and stop if you feel pain.

Additional Common Questions

When should I call my doctor about my arm muscles?

See your healthcare provider if you have any sudden changes in how your arm looks, or have muscle pain or weakness that doesn’t get better in a few days. Call your healthcare provider right away if you have muscle pain and:

  • Numbness or tingling.
  • Severe muscle weakness.
  • Swelling in your muscles.
  • Urine that’s very dark, red or brown.

A note from Cleveland Clinic

Your arm muscles help you move your arms, hands, fingers and thumbs. You have many muscles in your upper arm and forearm. They allow you to do activities that require big movements, like swinging a baseball bat. They also control small, precise movements such as writing your name. To avoid an injury, take time to warm up before exercising. And, don’t lift objects that are too heavy. See your healthcare provider if you have muscle swelling, severe pain, numbness or tingling.

Medically Reviewed

Last reviewed on 01/26/2022.

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