Brachialis Muscle: Location, Structure, Function and Clinical Relevance

The upper arm is located between the shoulder joint and the elbow joint.

It contains four muscles: three in the anterior compartment (biceps brachii, brachialis, coracobrachialis) and one in the posterior compartment (triceps brachii).

In this article, we will look at the anatomy of the upper arm muscles: their accessories, innervation, and actions.

Previous compartment

There are three muscles located in the anterior compartment of the upper arm: biceps brachii, coracobrachialis, and brachialis. All are innervated by the musculocutaneous nerve.

The arterial supply to the anterior compartment of the upper arm is via the muscular branches of the brachial artery.

biceps brachii

The biceps brachii is a two-headed muscle. Although most of the muscle mass is in the anterior part of the humerus, it has no link with the bone.

As the biceps brachii tendon enters the forearm, a sheet of connective tissue is shed, the bicipital aponeurosis . This forms the roof of the ulnar fossa and blends with the deep fascia of the anterior forearm.

The long head originates from the supraglenoid tubercle of the scapula, and the short head originates from the coracoid process of the scapula.

Both heads insert distally into the radial tuberosity and fascia of the forearm through the bicipital aponeurosis.

  • Forearm supination.
  • He also flexes his arm at the elbow and at the shoulder.

Innervation: musculocutaneous nerve.

The biceps tendon reflex examines the C6 spinal cord segment .


The coracobrachii muscle lies deep in the biceps brachii in the arm. It originates from the coracoid process of the scapula.

The muscle passes through the axilla and attaches to the medial side of the humeral shaft, at the level of the deltoid tubercle.

  • Flexion of the arm at the shoulder and weak adduction.

Innervation: musculocutaneous nerve.


The brachialis muscle lies deep in the biceps brachii and lies more distally than the other muscles of the arm. It forms the floor of the ulnar fossa.

It originates from the medial and lateral surfaces of the humeral axis and inserts into the tuberosity of the ulna just distal to the elbow joint.

  • Flexion at the elbow.

Innervation: musculocutaneous nerve, with contributions from the radial nerve.

Rear compartment

The posterior compartment of the upper arm contains the triceps brachii muscle, which has three heads. The medial head is deeper than the other two, which cover it.

The arterial supply to the posterior compartment of the upper arm is via the deep brachii artery.

brachial triceps

  • Long head: originates from the infraglenoid tubercle.
  • Lateral head: originates from the humerus, is superior to the radial groove.
  • Medial head: originates from the humerus, is inferior to the radial groove.

Distally, the heads converge on a tendon and insert into the olecranon of the ulna.

  • Arm extension at the elbow.

Innervation: radial nerve. A touch on the triceps tendon tests the C7 spinal segment.

Note: In some individuals, the long head of the triceps brachii is innervated by the axillary nerve.

Origins and insertions

It originates in the distal half of the anterior side of the humerus. In addition, the tendon of origin joins the medial and lateral intermuscular septa of the arm, two membranes that separate the flexor from the extensor muscles.

Distally, the muscle attaches to the tuberosity of the ulna, where its fibers are also connected to the joint capsule.


The nerve supply comes from the musculocutaneous nerve (C5-C7), however, in 70-80% of people, the muscle has double innervation with the radial nerve (C5-C6).

For the most part, the brachialis is below the biceps brachii and is therefore not easily palpable from the surface. The muscle has hardly any superficial parts that are located on its lateral border and distally.

Despite being in the deep part of the arm, the brachialis muscle continues to indirectly contribute to the surface anatomy.

This is because its large belly makes the biceps brachii appear much larger on the surface than it actually is. (“Behind every large biceps brachii is a large brachialis.”)

The brachialis is the strongest flexor of the elbow joint.

It is even a stronger flexor than the biceps brachii, because it is closer to the axis of the joint and, moreover, it only extends over one joint in contrast to the biceps brachii.

A small contraction of the muscle consequently leads to more flexion at the elbow.

Another function of the brachialis is to help maintain the tension found in the joint capsule, thereby preventing damage to the capsule during hyperextension.

Clinical relevance

Biceps tendon rupture

A complete rupture of any tendon in the body is rare. However, the long head of the biceps brachii is one of the most common tendons to tear.

This produces a characteristic sign when flexing the elbow, a bulge where the muscle belly meets, called the “Popeye sign.”

The patient would not notice much weakness in the upper limb due to the action of the brachialis and supinator muscles.

In cases of extreme elbow strain, inflammation of the brachial tendon (brachial tendonitis) or joint capsule injuries often occur.

Too many pull-ups, excessive tennis practice, or other improper elbow strain are among the typical causes.

As climbers are commonly affected by this condition, it is also known clinically as ‘ climber’s elbow ‘.

Classic symptoms include swelling, redness, and restricted and painful movements of the elbow.

Brachial pain

Brachial pain is inflammation of the brachial plexus that can cause sudden pain in the arm and shoulder followed by weakness or numbness.

This condition is referred to by many names, including Aldren Turner Parsonage syndrome, brachial plexitis, climbers’ elbow, brachial plexopathy, brachial neuropathy, and acute brachial radiolytic.

The exact cause of brachial pain is not known because the condition is comparatively rare. Brachial pain basically means that the nerves that control the shoulder, arm, and hands become inflamed.

It causes severe pain and when the pain subsides the shoulders weaken and limit movement.

The brachii muscle is not known to many people as it is covered by the biceps brachii. However, it is an important muscle required to flex the forearm at the elbow joint.

Brachial pain is a muscle overuse injury that begins with little pain and gradually progresses to excessive pain.

Some activities increase pain, including: playing the violin, lifting heavy objects, climbing, pulling regularly, and rotating the arm repeatedly with the elbow bent.

Brachial pain

If treated properly and on time, brachial pain can be cured within 6 weeks. Muscles weakened as a result of pain can be corrected in a few months.

The longer the brachial pain lasts, the longer the pain will heal.

Causes of brachial pain

The exact cause of brachial pain is unknown. Brachial pain is usually abrupt and can follow after recent illness, trauma, surgery, and immunization.

It has been seen that in most cases the pain begins at night and is confined around the shoulder region. The pain is sharp and throbbing and its intensity is very high.

Brachial pain is constant and can be aggravated by shoulder movements. Depending on the conditions, the pain can last from a few hours to several weeks.

The risk of brachial pain is increased in people involved in contact sports or activities that require excessive use of weapons such as gymnastics, weight lifting, rock climbing, bowling, and throwing sports.

Heavy work also increases the risk of this pain.

The body not warmed up properly before an activity, restricting the elbow, poor strength, flexibility, and injury to the elbow also increases the risk of brachial pain.

Brachial pain symptoms

Brachial pain begins with pain and continues to weaken the muscles. Some of the common symptoms associated with brachial pain include:

  • Sudden onset of pain
  • The arm muscle weakens.
  • Penetrating, sharp, or irritating pain.
  • The pain begins in the shoulder and upper arm.
  • Symptoms are felt on one side of the body.
  • Swelling in the elbow or above the elbow.
  • Pain and tenderness in the front of the elbow.
  • Unable to fully straighten or bend the elbow.
  • The pain is severe when trying to fully straighten the elbow.
  • The pain worsens with activities like rock climbing or throwing.
  • A cracking noise occurs when moving or touching the tendon or elbow.

Other symptoms of brachial pain include pain that only subsides after taking pain relievers and persists consistently for hours or weeks, depending on the severity of the condition.

In some cases, the shoulder muscles weaken or even paralyze when the pain recedes. If the nerve near the diaphragm is affected, the patient may experience shortness of breath.

The severity and duration of brachial pain symptoms vary depending on the physical condition of the patient.

Brachial pain diagnosis

Patients showing any symptoms of brachial pain should see their doctor immediately, whether they have any of the risk factors or not.

The doctor or healthcare provider performs electromyography or nerve conduction studies to determine whether or not a person suffers from brachial pain.

This test helps determine the exact amount of nerve damage. Other tests may also be done to assess movement and strength of the shoulder or to find wasted and painful muscles.

In some cases, the affected shoulder sticks out, so doctors need to check it.

Depending on the condition, doctors may order an MRI, CT scans, and X-rays of the neck and shoulder.

These tests help rule out other causes such as the tumor or slipped disc from pain. If patients have an underlying disease, the doctor may also order blood tests.

Brachial pain treatment

Doctors use a combination of medications and physical therapy to treat brachial pain. The first step in treating brachial pain involves the use of pain relievers that help reduce pain and inflammation.

Anti-inflammatory medications such as aspirin and ibuprofen or other pain relievers are generally prescribed.

Patients must make changes to decrease or modify movements and activities that can make symptoms worse.

Strengthening and stretching exercises are helpful in treating brachial pain but must be done correctly.

Learning the proper method is important and can be done at home or in the therapist’s office as appropriate. If your brachial pain symptoms do not improve, your doctor may suggest surgery, although it is rarely required.

In surgery, damaged nerves are repaired with grafts taken from other healthy nerves. Helps restore muscle function.

Hitting the affected area helps relieve brachial pain and reduce swelling.

A cold treatment should be applied to the affected area for 10/15 minutes every 2/3 hours immediately after any activity that may aggravate the symptoms of brachial pain.

However, those suffering from arthritis should take cold compression with care and after consultation, as it could increase their overall pain. Instead, you can use a warm compress .

For others, heat treatment for brachial pain can be done prior to stretching and strengthening exercises as prescribed by a therapist.

It can be done with a heat pack or a warm bath.

Exercises for brachial pain

Exercises for brachial pain can help rehabilitate the injury. It can also help restore tissue flexibility and normal movement in the joints.

Any training or stretching should not be painful and should involve a gentle release on the stretched muscle. There are a number of exercises that can help decrease and cure brachial pain.

It is advisable to consult a professional so that they can guide you in the correct performance of the exercises.

Some of the exercises that can help include: Brachialis Barbell Curl Exercise and PainBarbell Curls which help train the brachialis muscle.

In this exercise, keep your back straight and slowly raise the bar while bending your elbows in a controlled and even motion. The weight of the bar should be correlated with the strength of the arm muscle.

Light weights will not supplement the muscle, and anything too heavy can cause muscle damage.

Weighted hammer curls are an exercise for pain in the brachialis muscle. The hammer curl on the dumbbell exercises an area of ​​the biceps by bending the dumbbell toward the shoulder.

For this exercise, hold a dumbbell in each hand near your thigh with your palms facing your thigh and keeping your back straight.

Next, slowly lift the weights and bend both elbows, until the weights touch your shoulder. Keep your elbows to the side and press against your body so that only the brachialis muscle lifts the weights.

Continue with alternate arm dumbbell hammer loops until muscles are tight but not painful.

For arm extension exercises for brachial pain keep the right / left arm at the side and straighten the elbow as far as is comfortable.

Adjust straighter by pushing down on your forearm until you feel a gentle stretch in the inner section of your elbow. Hold the position for a few seconds and slowly return to where you started.