Final answer:
Rotation has the smallest range of motion in the lumbar spine. Flexion and extension, which involve decreasing and increasing the angle between the bones, respectively, occur more extensively. The cervical region, not the lumbar, has the greatest range of rotational movement. The correct option is (c) Rotation
Step-by-step explanation:
The movement with the smallest range of motion in the lumbar spine is rotation. The lumbar spine is much more limited in rotation compared to flexion and extension, which occur within the sagittal plane. The greatest range of motion for rotation is actually found in the cervical region of the vertebral column. The lumbar region's design prioritizes stability over flexibility, limiting its capacity to rotate significantly.
Flexion involves a decrease in the angle between the bones, which is an anterior (forward) bending motion. Extension is an increase in the angle between the bones, which involves a posterior-directed (backward) motion. The lumbar spine can perform both flexion and extension to a greater extent than rotation.
The function of the erector spinal muscles includes providing postural support and allowing motions of flexion and extension in the vertebral column, which indirectly aids the limited rotation that does occur in the lumbar region. The correct option is (c) Rotation