The brachialis
Brachialis · musculus brachialis
The workhorse muscle under the biceps that bends your elbow.
What it does
The brachialis lies underneath the biceps on the front of the arm and attaches to the ulna just below the elbow. Because it pulls on the ulna, which can't rotate, it bends the elbow with equal strength whether your palm faces up or down.
Surprising fact
The brachialis is the elbow's strongest bender, even though the biceps sitting on top of it gets all the credit.
Why it matters
A well-developed brachialis pushes the biceps up and out, so it shapes the arm. It is used every time you carry a shopping bag or bring a cup to your mouth.
Nearby
Read more
Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.