What spinal movement is best described by the occurrence in the transverse/horizontal plane, usually accomplished by side bending?

The movement being described involves the orientation and action of the spine in the context of bending to the side, which is specifically referred to as lateral flexion. This movement occurs in the transverse or horizontal plane, but primarily concerns the bending to the side rather than any twisting or rotation of the spine.

Spinal rotation refers to the movement around the vertical axis of the spine, allowing the torso to twist in one direction or the other. This may involve turning the shoulders and hips in opposition, which is different from simply bending to the side.

Spinal flexion and extension are movements that occur in the sagittal plane, involving forward bending (flexion) and backward bending (extension). These movements do not encapsulate the side bending described in the question.

Spinal hyperextension is an extension movement that goes beyond the neutral position of the spine, also situated in the sagittal plane, and does not relate to side bending either.

Understanding these distinctions is crucial in accurately identifying movements and ensuring proper alignment and range of motion during exercise or rehabilitation.