Anatomy · Muscles
The muscles of the body
A clear, referenced guide to the body's major muscles — what each one is, where it sits, the movement it produces and the problems that affect it, across 14 key muscles.
Abdomen
Arm
Back
Chest
Head
Hip
Leg
Shoulder
No match — try another muscle name.
See also
Bones of the skeleton · Organs of the body · Nerves · Blood vessels · Body systems
How to use this section
Structure, function, and what goes wrong
Each guide covers where the muscle runs, which joint it moves, which nerve supplies it and the injuries and clinical tests associated with it.
A muscle is defined clinically by four things: its origin, its insertion, the movement produced when it shortens, and its nerve supply. That last one matters most in practice — weakness in a specific pattern of muscles localises a problem to a particular nerve or nerve root, which is the basis of a neurological examination. Our nerves guides approach the same anatomy from the other direction.
Anatomical descriptions rely on a small set of position words used precisely: proximal and distal, medial and lateral, anterior and posterior. They are always relative to the standard anatomical position, not to how a body happens to be lying. All are defined in our glossary, and appear as clickable definitions throughout these pages.
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