Final answer:
The three motions for full closing in the lumbar spine are flexion, extension, and lateral flexion.
Step-by-step explanation:
The three motions for full closing in the lumbar spine include flexion, extension, and lateral flexion. Flexion and extension occur within the sagittal plane, where flexion involves an anterior bending and extension involves a posterior-directed straightening or backward bending. Lateral flexion, which occurs in the coronal plane, involves the bending of the spine to either the right or left side.
These movements are enabled by the symphysis joints formed by the intervertebral discs and the plane type of synovial joints between the articular processes of adjacent vertebrae. Rotation, which is the twisting motion of the spine, is largely prohibited in the lumbar region due to the orientation of the articular processes.