Brachioradialis
Brachioradialis
Pronunciation: BRAY-kee-oh-ray-dee-AL-iss
For beginners
Even though it's located in the forearm, this muscle actually bends your ELBOW, not your wrist — and it works hardest when your palm faces sideways, like holding a hammer.
Show the advanced explanation
Its mechanical advantage peaks in the mid-pronation/supination (neutral) position, which is why neutral-grip exercises like the hammer curl load it more than either a fully supinated or fully pronated curl.
Structure & function
- Location
- A muscle on the thumb side of the forearm, forming the prominent bulge visible when the elbow is flexed against resistance with the thumb up.
- Origin
- Lateral supracondylar ridge of the humerus (just above the lateral epicondyle).
- Insertion
- Styloid process of the radius, near the wrist.
- Main action(s)
- Flexes the elbow; despite living in the forearm, it does not act on the wrist at all. It is most mechanically effective when the forearm is midway between palm-up and palm-down (a neutral, 'hammer' grip).
- Joint(s) crossed
- Elbow joint
- Movement plane
- sagittal
- Innervation
- Radial nerve (C5–C6)
- In daily movement
- Assists any elbow-bending task, especially those done with a neutral (thumb-up) grip, like carrying a suitcase or lifting a hammer.
- In exercise
- A significant contributor to elbow flexion in neutral-grip exercises like the hammer curl, working alongside the brachialis.
- Commonly confused with
- Its name ('brachio' + 'radialis') and forearm location often lead people to assume it is a wrist muscle, when it is actually purely an elbow flexor.
- Common misconceptions
- It is not part of 'the forearm muscles' functionally, even though it's located there — it belongs functionally with the elbow flexors.
Exercises that use this muscle
As a secondary / stabilizer
- Hammer Curl (secondary)
⚠ Safety note
Rarely a source of isolated injury; general elbow-flexor precautions apply.
Sources
“The brachioradialis flexes the elbow and is most mechanically effective with the forearm in a neutral position.”
Anatomy and Physiology 2e — OpenStax, Rice University · Ch. 11.5 Muscles of the Pectoral Girdle and Upper Limbs
Peer-reviewed textbook · License: CC BY-NC-SA 4.0 · Last checked 2026-07-19
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