_g_, Radius; _12_, large (third) metacarpal bone. (After
Ellenberger-Baum, Anat. für Künstler.)
]
=Movements.=—Taking the joint as a whole, the chief movements are
flexion and extension. In the standing position the joint is extended.
When the joint is flexed, slight lateral movement and rotation can be
produced by manipulation. The anterior part of the capsule is, of
course, tense during flexion, the posterior part in extension.
The movement practically all occurs at the radio-carpal and
intercarpal joints, the articular surfaces of which are widely
separated in front during flexion, but remain in contact behind. The
distal row remains in contact with the metacarpus. The intermediate
and ulnar carpals move together as one piece, but the radial does not
move so far as the intermediate, so that the anterior and interosseous
ligaments connecting these bones become tense and oblique in
direction.