Espiral AtlasCarpometacarpal and intermetacarpal joints
articulationes carpometacarpales et intermetacarpales
Study entry
Classification
Plane synovial joints, except the carpometacarpal joint of the thumb (trapezium–1st metacarpal), which is saddle-shaped and has its own cavity.
Surfaces
Distal row of the carpus with the bases of the metacarpals; in the intermetacarpal joints, the lateral surfaces of the bases.
Capsule
The four medial carpometacarpal joints and the three intermetacarpal joints have a common capsule and cavity. That of the thumb has its own, lax capsule. Palmar, dorsal and interosseous carpometacarpal and intermetacarpal ligaments; the superficial and deep transverse metacarpal ligaments keep the heads from moving apart.
Movements
That of the thumb performs flexion-extension, abduction-adduction, circumduction and some rotation, and is where opposition takes place. Those of the 2nd and 3rd fingers hardly move; that of the 4th a little; that of the 5th moderately.
Blood supply
Periarticular anastomoses of the carpus and the hand: dorsal and palmar carpal arches, deep palmar arch and metacarpal arteries.
Innervation
Anterior interosseous branch of the median, posterior interosseous branch of the radial and dorsal and deep branches of the ulnar.
Clinical
When the palm is cupped (tips of the thumb and little finger together), two thirds of the movement is at the carpometacarpal joint of the thumb.
Source: cap. 3, «Articulaciones del miembro superior: articulaciones carpometacarpianas e intermetacarpianas»