Metacarpal 2 (right) — second metacarpal (index)

Function

The longest metacarpal, rigidly keyed into the trapezoid and capitate — the fixed axis of the hand's arch.

Landmarks

• Base
• Shaft
• Head (knuckle)

Articulations (joints)

• Trapezoid
• Adjacent metacarpals (interosseous ligaments)
• Proximal phalanx of the index (metacarpophalangeal joint)

Clinical relevance

Boxer's fractures classically hit the fifth, but axial load through the index ray shears the second metacarpal's base in carpometacarpal dislocation.