Metacarpus

Metacarpus indicates the hand section comprising five metacarpal bones and corresponding to the palm region. It is analogous to the metatarsus of the foot.

Bony framework:

• The bony framework consists of five metacarpal bones. The 1st metacarpal corresponds to the thumb, while the 2nd to 5th metacarpals correspond to the index, middle, ring, and little fingers.

• Each metacarpal bone consists of a base, a shaft (body), and a distal head.

• The bases of metacarpals articulate with the distal row of carpal bones, forming five carpometacarpal joints. The 1st carpometacarpal joint, located between the trapezium and the 1st metacarpal, facilitates extensive mobility for the thumb. However, the remaining carpometacarpal joints have limited gliding movement for the other digits.

• The distal heads of metacarpals articulate with the proximal phalanges, forming metacarpophalangeal joints.

Ligaments:

• Palmar ligaments and medial and lateral collateral ligaments reinforce the fibrous capsule of each metacarpophalangeal joint.

• Deep transverse metacarpal ligaments stabilize the skeletal framework of the metacarpus by interconnecting the fingers (except the thumb). They attach to the palmar ligaments and the extensor hoods at the metacarpophalangeal joints.

• Extensor hood

Muscles, tendons, innervation, and vasculature:

• For information about the muscles and neurovasculature of the metacarpus, please refer to the description of the hand.