FLEXION – In the limbs—articulation of a joint or joints so that the angle between the bones becomes smaller.
At the poll, there are three directions of movement, the first two of which are described as flexions and involve motion of the atlanto-occipital joint:
*Direct or longitudinal flexion brings the chin toward the underside of the neck.
*Lateral flexion closes the angle between the cheek and the side of the neck.
*Rotation (twisting) occurs at the atlanto-axial joint and causes tilting of the head.
In the rest of the spine, movements occur in the same three directions as at the poll: flexion-extension (rounding-hollowing); lateral (left-right) bending, and twisting. The combination of these movements creates carriage, bend, displacement of the ribcage, etc.
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