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.
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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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.
Muscles on both the underside and the top of your forearm allow you to:
Muscles located deep inside of your forearm have several jobs:
Your upper arm muscles help you move your arms. They have different jobs based on their location. They help you:
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:
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:
Superficial muscles on the top of your forearm include:
These muscles sit under the superficial muscles on the underside of your forearm. They are:
Muscles located deep under your skin on the top of your forearm are:
You have four muscles in your upper arm, which is the area between your shoulder and your elbow. Your upper arm muscle anatomy includes:
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.
A few conditions that affect your arm muscles include:
Problems in your arm muscles can cause:
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.
Depending on the location and severity of the injury, your healthcare provider may recommend:
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.
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:
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.
Last reviewed by a Cleveland Clinic medical professional on 01/26/2022.
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