First metacarpal
Os metacarpi I
SkeletalSkeletonArmLeft and right
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- What it is
- Long bone of the palm behind the thumb, with a base at the carpus, a slender shaft and a rounded head forming the knuckle.
- Function
- Its mobile saddle joint lets the thumb oppose the fingers.
- Size
- ≈ 37 mm long
- Clinical note
- A Bennett fracture is an intra-articular fracture of its base.