Third metacarpal bone
The third metacarpal bone is a little smaller than the second.
The dorsal aspect of its base presents on its radial side a pyramidal eminence, the Third [metacarpal styloid process|styloid process], which extends upward behind the capitate; immediately distal to this is a rough surface for the attachment of the extensor [carpi radialis brevis muscle].
The carpal articular facet is concave behind, flat in front, and articulates with the capitate.
On the radial side is a smooth, concave facet for articulation with the second metacarpal, and on the ulnar side two small oval facets for the fourth metacarpal.