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Muscle guide · Arms

Brachialis

Also called muscle under the biceps

The brachialis sits on the lower front of the upper arm, underneath the biceps, running from the arm bone to the forearm bone just below the elbow.

It is a pure elbow flexor: it bends the elbow whether your palm faces up, down or in, and does not twist the forearm. Without supination it is the strongest elbow flexor there is.

5 exercises1 stretches6 with 3D demos3 sourcesUpdated 17 October 2026

Where the brachialis is and what it does

Shaded: the biceps area. It marks the region, not the exact outline of the brachialis.
Starts at (origin)
The lower half of the front of the upper arm bone.Distal anterior humerus
Attaches to (insertion)
The front of the little-finger-side forearm bone, just below the elbow.Ulnar tuberosity and coronoid process
What it does
  • Bends the elbow in every hand position: lifting a mug, carrying a box, a reverse curl.Elbow flexion (a pure flexor)
Nerve supply
Mostly the musculocutaneous nerve (C5, C6), often with a branch from the radial nerve.

Source 1

Exercises for the brachialis

It works in every curl. With the palm down the biceps is at a mechanical disadvantage, so reverse and hammer curls leave more of the load to the other flexors. No study has measured which exercises work it hardest; these load its actions.

Alternating hammer curl demonstrated on the 3D figure3D demoAlternating hammer curlIntermediate · A dumbbellDumbbell reverse curl demonstrated on the 3D figure3D demoDumbbell reverse curlIntermediate · A dumbbellCable rope hammer curl demonstrated on the 3D figure3D demoCable rope hammer curlBeginner · A cable machineDumbbell biceps curl demonstrated on the 3D figure3D demoDumbbell biceps curlBeginner · A dumbbellChin-up demonstrated on the 3D figure3D demoChin-upAdvanced · Pull-up bar

Stretches for the brachialis

Standing biceps stretch demonstrated on the 3D figure3D demoStanding biceps stretchBeginner · No equipment

Problems linked to the brachialis

Strains, bone in the muscle and tendon pain

Isolated tears are documented but rarer than biceps injuries, mostly from heavy loading. After a bad bruise, bone can form in the muscle (myositis ossificans), usually managed conservatively. Tendinopathy where it attaches, felt in the elbow crease, is rare.

Source 1

Routines that train it

Arm workout

Biceps, triceps and forearms: curls, hammer curls, skull crushers, pushdowns, concentration curls and dips.

35 minBeginner7 movesA dumbbell, A bench or box

Questions people ask

What does the brachialis do?

It bends the elbow, in every hand position. It does not twist the forearm.

How do you train the brachialis?

Any curl works it; hammer and reverse curls take the biceps' advantage away, leaving more work to the brachialis and brachioradialis.

Is the brachialis stronger than the biceps?

As an elbow flexor, the muscle-specific StatPearls chapters describe the brachialis as the primary one; the biceps is mainly a supinator.

Muscles it works with

Sources

  1. StatPearls · Anatomy, Shoulder and Upper Limb: Brachialis Muscle (2023)
  2. StatPearls · Anatomy, Shoulder and Upper Limb: Biceps Muscle (2024)
  3. Kleiber 2015 · Biceps and brachioradialis activity with different hand positions (Front Physiol)

Anatomy and movement education, not a diagnosis or treatment plan. If you have pain that follows an injury, is severe or getting worse, or comes with numbness, weakness or swelling, get it assessed. Health disclaimer.