A lumbosacral flexion-extension X-ray are dynamic side-view radiographs of the lower spine taken while you bend forward (flexion) and backward (extension). They assess spinal alignment and motion to detect instability, spondylolisthesis or abnormal vertebral translation/angulation not seen on static films. Results guide diagnosis and treatment planning for lower back pain or suspected mechanical instability.

An X‑ray of the lumbosacral (LS) spine lateral flexion is a pair of side‑bending radiographs taken while the patient bends laterally left and right. They evaluate spinal alignment and mobility, detect dynamic instability (e.g., spondylolisthesis), assess fusion or degenerative changes, and help guide treatment. It’s a quick, low‑dose ionizing‑radiation study performed standing or sitting under radiographer guidance.

Patient positioned in true lateral (standing or lateral recumbent) with pelvis and shoulders stacked, hips and knees flexed to reduce lumbar lordosis. Arms raised or supported forward out of the field. Center the lumbosacral junction on the image receptor so the sagittal plane is parallel to the detector; direct the central x‑ray beam perpendicular to the lumbosacral junction. Expose on suspended respiration.

Flexion and extension X‑rays are dynamic spine radiographs taken in forward and backward bending to reveal abnormal motion between vertebrae. They detect instability (excessive translation or angulation), occult spondylolisthesis, ligamentous injury, and alignment changes not seen on static images. They're commonly used for cervical and lumbar assessment, postoperative fusion evaluation, and to guide surgical or conservative management.

Sacral flexion (nutation) is the forward/inferior tilt of the sacral base relative to the ilia—apex moves posterior—opening the pelvic outlet. Sacral extension (counternutation) is the backward/superior tilt of the sacral base—apex moves anterior—enlarging the pelvic inlet. These small sacroiliac movements occur with trunk and pelvic motion and affect load transfer, spinal mechanics, and childbirth.

Lateral flexion of the lumbar spine is side‑bending of the lower back in the coronal plane. It’s produced by unilateral action of muscles like quadratus lumborum, ipsilateral erector spinae and obliques, causing narrowing of intervertebral spaces on the same side and opening on the opposite. Lumbar lateral flexion is typically about 15–20° per side and aids trunk mobility and balance.