The thumb's pinching muscle
Adductor pollicis · musculus adductor pollicis
A deep palm muscle that pulls the thumb against the side of the hand for a strong pinch.
What it does
The adductor pollicis lies deep in the palm, fanning from the middle metacarpals to the base of the thumb. It pulls the thumb towards the palm, the movement you use to hold a key or a sheet of paper between thumb and index finger.
Surprising fact
Doctors test it by asking you to grip a sheet of paper between thumb and index finger while they pull; if the nerve is weak, the thumb's tip bends to compensate, a sign named after the doctor Jules Froment.
Why it matters
It is supplied by the ulnar nerve, so ulnar nerve damage weakens your pinch even though the thumb's other muscles still work.
Nearby
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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.