First metacarpal (right) (Os metacarpale primum)
Educational content only — not medical advice.
Anatomy
The metacarpal of the thumb in the right hand: a tubular shaft with a basal end resting on the carpals and a rounded head articulating with the proximal phalanx. The shortest and thickest, its rotation disabled in favour of opposition; the opponens pollicis rides on its shaft.
Clinical notes
Bennett fracture at its base with the trapezium splits the first metacarpal and wrecks opposition; the muscle pull displaces the fragment, so surgical fixation is often required.
Related structures
Educational references
FAQ
What is the role of the First metacarpal (right)?
The metacarpal of the thumb in the right hand: a tubular shaft with a basal end resting on the carpals and a rounded head articulating with the proximal phalanx. The shortest and thickest, its rotation disabled in favour of opposition; the opponens pollicis rides on its shaft.
Why is the First metacarpal (right) clinically important?
Bennett fracture at its base with the trapezium splits the first metacarpal and wrecks opposition; the muscle pull displaces the fragment, so surgical fixation is often required.
Source & license
Derived from Z-Anatomy (Gauthier Kervyn et al.), CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/); upstream geometry from BodyParts3D, © The Database Center for Life Science. license details