Corpus: Carpometacarpal joint
Definition
The carpometacarpal joints are the joint connections between the distal row of carpal bones (carpus) and the metacarpal bones of the hand (metacarpus).
Anatomy
The carpometacarpal articulations between the carpus and metacarpal bones II-V are part of the metacarpal joint. They are classified as amphiarthroses, stabilized by numerous ligaments resulting in limited mobility. These ligaments include:
- palmar carpometacarpal ligaments
- dorsal carpometacarpal ligaments
- palmar metacarpal ligaments
- dorsal metacarpal ligaments
Only the connection between the trapezium bone and the first metacarpal bone, known as the carpometacarpal joint of the thumb ("thumb saddle joint"), is a true freely movable joint.
Biomechanics
The carpometacarpal joints, like the intercarpal articulations, are termed "accessory joints," which increase the mobility of the carpal bones among each other, thereby enhancing the mobility of the adjacent main joint (wrist).