First Metacarpal
The structure indicated is the
first metacarpal of the hand.
There are
three groups of bones in the hand:
- Carpal bones (8 in total)
- Metacarpal bones
- Phalanges
The carpal bones are separated into
two rows:
- Proximal row
- Distal row
There are
5 metacarpal bones numbered 1 to 5 and are located between the carpal bones and the phalanges. The
first metacarpal bone is associated with the
thumb, the
5th metacarpal bone is associated with the
little finger. The joints between the carpals and the metacarpals are known as
carpometacarpal joints. The joints between the metacarpals and the proximal phalanges are known a
metacarpophalangeal (MCP) joints. In addition, the bases of the metacarpal bones articulate with each other.
The first carpometacarpal joint of the thumb is particularly important; the articulation between the first metacarpal and the trapezium bone forms a
saddle joint and allows a wide range of movement, including flexion, extension, abduction, adduction, circumduction and opposition.
The metacarpal bones consist of the following parts:
Learn more about the anatomy of the
bones of the hand in this tutorial.