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The brachialis is a muscle in the upper arm that flexes the elbow. It is located in the anterior compartment of the arm, deep to the biceps brachii. The brachialis is the prime mover of elbow flexion, generating about 50% more power than the biceps. It is considered a pure flexor of the forearm at the elbow and is the only muscle that produces force during elbow flexion. The brachialis is also involved in precision movements, such as carefully lowering a teacup onto a flat surface.
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What You'll Learn
- The brachialis is the prime flexor of the forearm at the elbow joint
- It is located in the anterior compartment of the arm
- The muscle is commonly injured by repetitive forceful contractions
- It is innervated by the musculocutaneous nerve
- The brachialis is the strongest flexor of the elbow in the absence of supination
The brachialis is the prime flexor of the forearm at the elbow joint
The brachialis is a vital muscle in the forearm, acting as the primary flexor at the elbow joint. It is located in the anterior (flexor) compartment of the arm, deep to the biceps brachii. The brachialis is broad, with its widest point in the middle, and it can sometimes be divided into two parts. It is also attached to the intermuscular septa of the arm on both sides, with a more extensive connection to the medial intermuscular septum. The muscle originates from the anterior surface of the distal half of the humerus, just below the insertion of the deltoid muscle.
The brachialis is a powerful flexor, producing the majority of force during elbow flexion. It is the only pure flexor at the elbow joint, and it operates independently of forearm pronation or supination. This muscle is essential for steadying the elbow during controlled extension, allowing for precise movements such as carefully lowering a teacup. The brachialis is also susceptible to injury from repetitive forceful contractions or muscular contractions with the arm in hyperextension, a common issue for climbers due to the pronated hand position.
The tendon of the brachialis inserts onto the tuberosity of the ulna, with an accessory attachment to the radius or bicipital aponeurosis in some cases. The muscle is supplied by the musculocutaneous nerve (C5, C6), and a small lateral portion is innervated by the radial nerve (C7). Additionally, the brachialis receives blood supply from tributaries of the brachial artery and the radial recurrent artery, with occasional contributions from other arteries, such as branches of the ulnar collateral arteries.
The brachialis is clinically significant, and its function can be assessed through manual resistance tests. Impaired elbow flexion can result from various causes, including neurologic, neurovascular, muscle rupture, or traumatic events. In certain surgical procedures, the brachialis tendon transfer is used to reconstruct the flexor digitorum profundus and flexor pollicis longus after brachial plexus injuries.
The brachialis is an important muscle for upper body exercises such as pull-ups and elbow curls, and its overuse can lead to inflammation of the tendon, known as brachialis tendonitis. Climbers' elbow is a common form of tendonitis in climbers due to the repeated pronation and hyperextension of the hand and wrist.
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It is located in the anterior compartment of the arm
The brachialis muscle is located in the anterior compartment of the arm. It is a prime flexor of the forearm at the elbow joint, generating about 50% more power than the biceps. It is also known as the workhorse of the elbow. The brachialis is the only pure flexor of the elbow joint, producing the majority of force during elbow flexion. It is not affected by pronation or supination of the forearm and does not participate in pronation and supination due to its lack of attachment to the radius.
The brachialis muscle is located deep to the biceps brachii. It is a broad muscle, with its broadest part located in the middle rather than at either of its extremities. It is sometimes divided into two parts and may fuse with the fibres of the biceps brachii, coracobrachialis, or pronator teres muscles. The brachialis muscle contributes to the formation of the floor of the cubital fossa, also known as the elbow pit.
The brachialis muscle originates from the anterior surface of the distal half of the humerus, just distal to the insertion of the deltoid muscle. It is also attached to the intermuscular septa of the arm on either side, with a more extensive attachment to the medial intermuscular septum. The fibres of the brachialis muscle converge to a thick tendon, which is inserted into the tuberosity of the ulna and the rough depression on the anterior surface of the coronoid process of the ulna.
The brachialis muscle is commonly injured by repetitive forceful contractions or muscular contractions with the arm in hyperextension. This is often seen in climbers due to the pronation of the hand and the extended starting position. Physical activities that involve a lot of pull-ups, curls, and rope climbing can also cause brachialis muscle pain.
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The muscle is commonly injured by repetitive forceful contractions
The brachialis muscle is a major flexor of the forearm at the elbow joint. Located in the anterior compartment of the arm, it works closely with the biceps brachii and brachioradialis muscles to allow for elbow flexion and appropriate bending of the elbow.
Hyperextension of the elbow joint, forceful or repetitive strain, and sudden impact can also cause brachialis injuries. For example, falling on one's arms or hitting the elbow against a hard object can result in a brachialis tear due to the sudden and forceful impact.
The symptoms of a brachialis injury include pain, swelling, numbness, and weakness in the forearm or fingers. Pain may also extend to the back of the hand, especially the thumb and index finger. Brachialis pain is often confused with lateral epicondylitis, commonly known as tennis elbow, which involves inflammation of the tendons. However, a strained brachialis involves injury to the muscle rather than tendon inflammation.
If you suspect a brachialis injury, it is important to seek medical attention for a proper diagnosis and treatment. Treatment options may include physical therapy, ultrasound, massage, electrical stimulation, and following the P.O.L.I.C.E. principle (protection, optimal loading, ice, compression, and elevation).
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It is innervated by the musculocutaneous nerve
The brachialis muscle is a prime flexor of the forearm at the elbow joint. It is located in the anterior (flexor) compartment of the arm, deep to the biceps brachii. The brachialis is the only pure flexor of the elbow joint, producing the majority of force during elbow flexion. It is also involved in precision movements, such as carefully lowering a teacup onto a flat surface.
The brachialis muscle is innervated by the musculocutaneous nerve, which is a major peripheral nerve of the upper limb. The nerve emerges as the terminal branch of the lateral cord of the brachial plexus, from the C5-C7 nerve roots. The musculocutaneous nerve first enters the coracobrachialis muscle and gives branches to it. It then passes through the flexor compartment of the upper arm, innervating both the brachialis and biceps brachii muscles.
The musculocutaneous nerve provides motor functions to the muscles in the anterior compartment of the arm, including the coracobrachialis, biceps brachii, and brachialis. It also gives rise to the lateral cutaneous nerve of the forearm, which innervates the lateral aspect of the forearm. This nerve initially enters the deep forearm but then pierces the deep fascia to become subcutaneous.
Injury to the musculocutaneous nerve can cause weakness of arm flexion and sensory loss along the lateral forearm. It can also result in Erb's palsy, affecting elbow flexion. Lesions of the nerve are rare and typically occur due to injury in the upper arm or paravenous injection in the forearm.
The brachialis muscle also receives dual innervation, with medial innervation from the musculocutaneous nerve and lateral innervation from the radial nerve. The radial nerve descends in the groove between the brachialis and brachioradialis muscles, above the elbow.
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The brachialis is the strongest flexor of the elbow in the absence of supination
The brachialis muscle is a prime flexor of the forearm at the elbow joint. Located in the anterior (flexor) compartment of the arm, it is a broad muscle with its broadest part in the middle. It is also known as the "workhorse of the elbow". The brachialis is the only pure flexor of the elbow joint, producing the majority of force during elbow flexion.
The brachialis is located on the anterior surface of the shaft of the humerus, deep to the muscle belly of the biceps brachii and distal to its tendon. The biceps brachii muscle is located immediately anterior to the brachialis, as are the brachial vessels, musculocutaneous, and median nerves. The humerus and the capsule of the elbow joint lie posterior to the muscle. The brachialis is separated from the triceps brachii and the ulnar nerve by the medial intermuscular septum and pronator teres.
The brachialis muscle commonly becomes injured through repetitive forceful contractions or muscular contractions with the arm in hyperextension. This is often seen in climbers due to the pronation of the hand and the extended starting position. Physical activities such as pull-ups, curls, and rope climbing can also cause brachialis muscle pain.
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Frequently asked questions
The brachialis muscle is located in the upper limb of the body, in the anterior (flexor) compartment of the arm, deep to the biceps brachii.
The brachialis muscle is the prime flexor of the forearm at the elbow joint. It is the only pure flexor of the elbow joint and is responsible for producing the majority of force during elbow flexion.
The brachialis muscle is broad and fusiform in shape. It is broadest in the middle rather than at its extremities.
To test the strength of your brachialis muscle, place your elbow at a 90-degree flexion with your forearm fully pronated. You can also flex your forearm at the elbow joint against resistance and palpate the muscle.
