Table of ContentsView AllTable of ContentsArm Muscle AnatomyFunctionAssociated ConditionsTests
Table of ContentsView All
View All
Table of Contents
Arm Muscle Anatomy
Function
Associated Conditions
Tests
Arm muscle anatomy refers to the location and function of the muscles of the arms. These muscles attach to the shoulder blade, upper arm bone (humerus), forearm bones (radiusandulna), wrist, fingers, and thumbs.
Anatomical Structure and Location of Arm Muscles
There are 24 different muscles that make up each arm, and they control movement of the elbow, forearm, wrist, and fingers. The arm muscle groups consist of the upper arm and lower arm.
The major muscles of the arm are the four upper arm muscles. These are considered to be the major muscles of the arm because they are larger than the muscles of the lower arm.
The 20 muscles of the lower arm are divided into anterior (front of the arm) and posterior (back of the arm). They can be superficial (near the skin) or deep (underlying the superficial group).
Flexors are muscle groups that bend and move body parts, such as the arm, hand, or fingers closer to the body, while extensors are muscle groups that extend and move body parts away from the body.
Upper Arm Muscles (Between the Shoulder and the Elbow)
The four upper arm muscles originate from the front portion of the shoulder blade, called thescapula, or from the upper position of the humerus, the long bone that makes up the upper arm.
There are three muscles on the front of the upper arm and one on the back:
Anterior Lower Arm Muscles (Front of the Forearm)
There are four superficial muscles in the front of the lower arm, the area between the elbow and wrist:
There is one muscle in the intermediate (middle) layer of the anterior forearm muscles:
The three deep muscles of the front of the arm sit closest to the bone:
Posterior Lower Arm Muscles (Back of the Forearm)
There are seven superficial muscles of the back of the lower arm:
The five deep muscles of the back of the lower arm underlie the superficial muscles:
Function of Arm Muscles
Themuscles of the upper arm, the area between the shoulder and elbow, primarily control movement of the elbow. The biceps brachii, coracobrachialis, and brachialis all controlflexionat the elbow joint, or bending of the elbow. The coracobrachialis also controls adduction, a movement that brings the arm closer to the body.
Thebrachioradialis of the lower arm musclesalso contributes to elbow flexion. The triceps brachii, along with a small contribution from the anconeus, controls the opposite motion, extension, of the elbow. The biceps brachii and triceps brachii also contribute to flexion and extension of the shoulder, respectively.
Themuscles of the lower armcontrol wrist, forearm, and finger movement. The flexor carpi radialis, flexor carpi ulnaris, and palmaris longus flex, or bend, the wrist, while their counterparts, the extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris, extend the wrist.
Thepronator teres and pronator quadratusfunction to pronate the forearm, the motion of turning the forearm so that the palm faces the ground. Their counterpart, the supinator, controlssupinationof the forearm, the motion of turning the forearm so that the palm faces up. The biceps brachii and brachioradialis also help supinate the forearm.
Theflexor digitorum superficialis and flexor digitorum profunduscontrol bending of the fingers, while the extensor digitorum controls extending of the fingers. The index and pinky fingers also receive additional input from the extensor indicis, which extends the index finger, and the extensor digiti minimi, which extends the pinky finger.
Thethumbhas its own set of muscles that includes the flexor pollicis longus, which bends the thumb, the extensor pollicis longus and extensor pollicis brevis, which extend the thumb, and the abductor pollicis longus, which abducts the thumb, the perpendicular movement of the thumb away from the palm of the hand.
Conditions Associated With Arm Muscles
Neuromuscular Disorders
Neuromuscular disordersare conditions that affect the nerves that send electrical signals to muscles to control movement. Symptoms of these disorders include muscle weakness, muscle wasting (atrophy), muscle twitching, spasms, or muscle pain.
Many neuromuscular disorders are inherited, meaning they run in families. However, they also can be acquired due to causes not fully understood, including spontaneous gene mutations and immune system disorders. Some areautoimmune diseases.
Common neuromuscular disorders that can affect the muscles of the arms include:
Injury
Common injuries that affect the muscles of the arms include:
Allowing injured or overused muscles to rest can help ease the pain and discomfort. Seeing a physical therapist can help you return to your daily activities and exercises without limitations.
Arm Muscle Tests
Different tests are used to confirm a diagnosis of an injury or disorder of the muscles of the arm, including:
Summary
There are 24 different muscles that make up the upper and lower arm. Each muscle controls a specific movement, such as extension, flexion, pronation, and supination.
Problems can result from injury, repetitive use, or neuromuscular disorders that cause weakness of the elbow, forearm, wrist, or finger muscles. This weakness can interfere with your ability to perform daily tasks.
Talk to a healthcare provider if you’re experiencingmuscle pain, weakness, or wasting. The provider can run tests to determine the cause and get you the treatment you need.
3 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.The University of Michigan.Muscles of the upper limb - listed alphabetically.Forro SD, Munjal A, Lowe JB.Anatomy, shoulder and upper limb, arm structure and function. In: StatPearls.StatPearls Publishing. 2023.MedlinePlus.Neuromuscular disorders.
3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.The University of Michigan.Muscles of the upper limb - listed alphabetically.Forro SD, Munjal A, Lowe JB.Anatomy, shoulder and upper limb, arm structure and function. In: StatPearls.StatPearls Publishing. 2023.MedlinePlus.Neuromuscular disorders.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
The University of Michigan.Muscles of the upper limb - listed alphabetically.Forro SD, Munjal A, Lowe JB.Anatomy, shoulder and upper limb, arm structure and function. In: StatPearls.StatPearls Publishing. 2023.MedlinePlus.Neuromuscular disorders.
The University of Michigan.Muscles of the upper limb - listed alphabetically.
Forro SD, Munjal A, Lowe JB.Anatomy, shoulder and upper limb, arm structure and function. In: StatPearls.StatPearls Publishing. 2023.
MedlinePlus.Neuromuscular disorders.
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