Brachialis Muscle Overload – A Hidden Cause of Elbow, Shoulder, and Thumb Pain

What Is the Brachialis Muscle?

The brachialis muscle is a deep muscle located in the front of the upper arm. It connects the upper arm bone (humerus) to the forearm bone (ulna). Its main job is to bend the elbow, no matter how your forearm is rotated (palm up or down).

Because this muscle sits under the biceps, many people are not even aware it exists—until it becomes painful.

Another important role of the brachialis muscle is to protect the elbow joint capsule, preventing it from being pinched during movement.

Common Causes of Brachialis Muscle Pain

Pain related to brachialis muscle overload is often caused by:

• Carrying heavy objects with the elbow bent at about 90 degrees

• Sports injuries

• Compensation from problems in the wrist, elbow, or shoulder

• Long-term overuse without proper recovery

This condition is common in people who train, work physically, or sit at a desk with poor upper-limb mechanics.

Symptoms – Why the Pain Feels Confusing

One of the most misleading things about brachialis muscle overload is that the pain is often felt somewhere else.

Because the muscle lies deep under other tissues, the nervous system cannot clearly locate the source of pain. This results in referred pain, which may be felt in:

• The front of the shoulder

• The front of the elbow

• The base of the thumb

Pain usually gets worse when:

• Bending the elbow

• Lifting objects

• Performing pulling or carrying movements

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Why It’s Often Misdiagnosed

Most patients cannot correctly identify the source of the problem. They usually point to shoulder pain or thumb pain first.

During a proper physiotherapy assessment:

• Shoulder and wrist issues are ruled out

• Resisted elbow bending reproduces the symptoms

• If pain does not change with wrist position, the brachialis muscle is often the real cause

This is why many people struggle with chronic pain despite normal scans or previous treatments.

Physiotherapy Treatment for Brachialis Muscle Overload

Effective physiotherapy treatment focuses on:

• Manual therapy to release excessive muscle tension

• Gradual, progressive strengthening

• Improving the biomechanics of the entire upper limb

• Addressing compensations in the shoulder, elbow, and wrist

The goal is not only pain relief, but also restoring proper movement and preventing the problem from returning.

Why This Matters

If you have:

• Unexplained elbow pain

• Shoulder pain that doesn’t respond to treatment

• Thumb pain without clear injury

• Pain that worsens with lifting or bending the elbow

The brachialis muscle may be the missing piece.

References

1. Davies C., Davies A. Trigger Point Therapy. Vital Publishing, 2015.

2. Leonello D. T., Galley I. J., Bain G. I., Carter C. Brachialis Muscle Anatomy – A Cadaver Study. Journal of Orthopaedic Surgery, 2007.