Five basic movements in the spine are possible:
1. Flexion, or forward bending of the spine, in which the anterior surfaces of the vertebrae move closer to one another.
2. Extension is the return from a position of flexion to the anatomical position. It is the opposite of flexion. Going beyond the anatomical position (bending backward) is called hyperextension. Keep in mind that slight hyperextension is the normal position of the lumbar spine (also known as slight lordosis).
3. Lateral flexion, is bending sideways to the right or left. In this action the shoulders move toward the hip, or the hips (pelvis) move toward the shoulders when the hips are in a non-support hanging position.
4. Shoulder (shoulder girdle) rotation, is a twisting action around the long axis of the spinal column. In this movement the shoulders (or hips) are in motion. Shoulder rotation can also occur with the axis in the left or right side of the body.
5. Hip rotation. If you are positioned so that your body is hanging, supported by your arms, the abdominal or lower back muscles rotate your hips to the right or left while your shoulders remain stationary. This is also known as transverse pelvic girdle rotation. It can also occur when you are standing, but in that case the action and muscles involved are in the hip joints, not the midsection. Note that discussion here is of the movements seen in the lumbar spine. Analogous actions take place in the cervical spine but they will not be discussed.