The metacarpal bones are a group of five long bones that form the middle portion of the hand skeleton. They are positioned between the carpal bones and the phalanges. The metacarpals are analogous to the metatarsals in the foot.

The metacarpal bones appear tubular-shaped, and their distal ends are rounded, while the proximal ends are squarish. In the lateral view, the palmar surfaces of these bones are more concave than their dorsal surfaces.

The distal ends of the metacarpals articulate with the bases of the proximal phalanges, forming the metacarpophalangeal joints. In contrast, the proximal ends of these bones connect with the distal carpal bones, forming the carpometacarpal joints.

These bones lack individual names, and they are numbered from the radial side of the hand as the first metacarpal bone, second metacarpal bone, third metacarpal bone, fourth metacarpal bone, and fifth metacarpal bone. The spaces between the metacarpal bones are called the intermetacarpal spaces.

Additionally, several sesamoid bones usually lie on the palmar aspects at the heads of the metacarpal bones (most commonly, at the first, second and fifth metacarpophalangeal joints).

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Metacarpal bones